science/test/questions.forum.tsv

0	Cooling a cup of coffee with help of a spoon
1	Can I compute the mass of a coin based on the sound of its fall?
2	How does light bend around my finger tip?
3	How does gravity escape a black hole?
4	Did the Big Bang happen at a point?
5	Why are mirror images flipped horizontally but not vertically?
6	Do we know why there is a speed limit in our universe?
7	Book recommendations
8	What experiment would disprove string theory?
9	Why dont metals bond when touched together?
10	Why do ballpoint pens write better on pages that have pages below them?
11	What is Chirped Pulse Amplification, and why is it important enough to warrant a Nobel Prize?
12	Why does kinetic energy increase quadratically, not linearly, with speed?
13	What really allows airplanes to fly?
14	Why are four-legged chairs so common?
15	If I sliced the universe in half, would the slice go through a star?
16	Dont heavier objects actually fall faster because they exert their own gravity?
17	How do towels stay on hooks?
18	What exactly is a photon?
19	Does Earth really have two high-tide bulges on opposite sides?
20	Strange ice found in my garden
21	Why is the detection of gravitational waves so significant?
22	Surviving under water in air bubble
23	Why do we bend a book to keep it straight?
24	If photons have no mass, how can they have momentum?
25	Why doesnt matter pass through other matter if atoms are 99.999% empty space?
26	Why is Googles quantum supremacy experiment impressive?
27	Are units of angle really dimensionless?
28	Why dont electrons crash into the nuclei they orbit?
29	Why does space expansion not expand matter?
30	When separating an Oreo cookie, why does the cream stick to just one side only?
31	Why does NASA use gold foil on equipment and gold-coated visors?
32	How do moving charges produce magnetic fields?
33	How does a knife cut things at the atomic level?
34	Why do we not have spin greater than 2?
35	Why do shadows from the sun join each other when near enough?
36	Gauge symmetry is not a symmetry?
37	Why do we actually see the sun?
38	Whats the point of Hamiltonian mechanics?
39	Could Legolas actually see that far?
40	How do you make more precise instruments while only using less precise instruments?
41	Why does holding something up cost energy while no work is being done?
42	What makes a theory Quantum?
43	Given Newtons third law, why are things capable of moving?
44	Why does Stephen Hawking say black holes dont exist?
45	Why do sunbeams diverge even though the sun is much more than a few kilometers away?
46	How do I explain to a six year old why people on the other side of the Earth dont fall off?
47	Simple check for the global shape of the Earth
48	Why are the harmonics of a piano tone not multiples of the base frequency?
49	What is a field, really?
50	Why are the wet patches on these floor tiles circular?
51	Why is nuclear waste more dangerous than the original nuclear fuel?
52	Is $\pi^2 \approx g$ a coincidence?
53	Why does a mirror split my laser beam?
54	Why is my hand not burned by the air in an oven at 200 °C?
55	Why would spacetime curvature cause gravity?
56	Does someone falling into a black hole see the end of the universe?
57	Why are the windows of bridges of ships always inclined?
58	Does the Planck scale imply that spacetime is discrete?
59	Is temperature a Lorentz invariant in relativity?
60	Why do people categorically dismiss some simple quantum models?
61	If you view the Earth from far enough away can you observe its past?
62	Is time continuous or discrete?
63	How can you weigh your own head in an accurate way?
64	Why does my tea periodically alternate its rotational speed after stirring? (Link to video below)
65	How fast does gravity propagate?
66	How do I experimentally measure the surface area of a rock?
67	Is the butterfly effect real?
68	Why doesnt water boil in the oven?
69	A list of inconveniences between quantum mechanics and (general) relativity?
70	Why are there only derivatives to the first order in the Lagrangian?
71	Reading the Feynman lectures in 2012
72	Why is the vibration in my wire acting so oddly?
73	Why can I touch aluminum foil in the oven and not get burned?
74	Why does paper cut through things so well?
75	What does it mean for two objects to touch?
76	Why do spaceships heat up when entering earth but not when exiting?
77	Does a particle exert force on itself?
78	Why does Newtons Third Law actually work?
79	Why does ice cream get harder when colder?
80	Why does the humidifier make a stoves flame orange?
81	How does mass leave the body when you lose weight?
82	Is anti-matter matter going backwards in time?
83	Calculus of variations -- how does it make sense to vary the position and the velocity independently?
84	Why dont we use weights to store energy?
85	Why do wet objects become darker?
86	Why am I not burned by a strong wind?
87	The Role of Rigor
88	On this infinite grid of resistors, whats the equivalent resistance?
89	If all motion is relative, how does light have a finite speed?
90	Could we send a man safely to the Moon in a rocket without knowledge of general relativity?
91	Superfields and the Inconsistency of regularization by dimensional reduction
92	Is it necessary to consume energy to perform computation?
93	Toilet paper dilemma
94	Is it possible for information to be transmitted faster than light by using a rigid pole?
95	Why do electrons, according to my textbook, exist forever?
96	What happens to the energy when waves perfectly cancel each other?
97	Why does a helium filled balloon move forward in a car when the car is accelerating?
98	What is the actual significance of the amplituhedron?
99	Can the Heisenberg Uncertainty Principle be explained intuitively?
100	What, in simplest terms, is gauge invariance?
101	Can Maxwells equations be derived from Coulombs Law and Special Relativity?
102	Is the universe fundamentally deterministic?
103	Why are most metals gray/silver?
104	Is it possible to start fire using moonlight?
105	What are the justifying foundations of statistical mechanics without appealing to the ergodic hypothesis?
106	Books for general relativity
107	Why is glass transparent?
108	How can anything ever fall into a black hole as seen from an outside observer?
109	Whats inside a proton?
110	Why is oil a better lubricant than water?
111	Why do tuning forks have two prongs?
112	Why do fusion and fission both release energy?
113	Why is quantum entanglement considered to be an active link between particles?
114	Why are some people are claiming that the Big Bang never happened?
115	How do we know that radioactive decay rates are constant over billions of years?
116	How can I stand on the ground? EM or/and Pauli?
117	Is Angular Momentum truly fundamental?
118	What is $\Delta t$ in the time-energy uncertainty principle?
119	Why the Principle of Least Action?
120	Why does the Suns (or other stars) nuclear reaction not use up all its fuel immediately?
121	Intuitively, why are bundles so important in Physics?
122	Why does a sticker slowly peel off, but if it is pulled quickly it tears?
123	What is known about the topological structure of spacetime?
124	Does the $\frac{4}{3}$ problem of classical electromagnetism remain in quantum mechanics?
125	How can we see an atom now? What was the scale of this equipment?
126	Is there such thing as imaginary time dilation?
127	Thought experiment - would you notice if you fell into a black hole?
128	Explain it to me like Im a physics grad: Greenhouse Effect
129	QM without complex numbers
130	What Is Energy? Where did it come from?
131	Why is filling a balloon from your mouth much harder initially?
132	If gravity isnt a force, then why do we learn in school that it is?
133	If I pull a metal bar for long enough with a constant small force, will it eventually break?
134	Which is stronger, a rope without knots or a rope with knots?
135	Would a pin head heated to 15 million degrees Celsius kill everyone in a 1000 mile radius?
136	Why is there a scarcity of lithium?
137	Why do most formulas in physics have integer and rational exponents?
138	Is there something similar to Noethers theorem for discrete symmetries?
139	What is a good introductory book on quantum mechanics?
140	Best books for mathematical background?
141	What is the physical meaning of commutators in quantum mechanics?
142	Differentiating Propagator, Greens function, Correlation function, etc
143	What justifies dimensional analysis?
144	How is a quantum superposition different from a mixed state?
145	Why dont miners get boiled to death at $4$ km deep?
146	Trace of a commutator is zero - but what about the commutator of $x$ and $p$?
147	About the complex nature of the wave function?
148	Why was carbon-12 chosen for the atomic mass unit?
149	Why does the shower curtain move towards me when I am taking a hot shower?
150	Where is the flaw in this machine that decreases the entropy of a closed system?
151	Why does the atmosphere rotate along with the earth?
152	Why does hot water clean better than cold water?
153	What is the speed of sound in space?
154	How can a black hole produce sound?
155	What is the proper way to explain the twin paradox?
156	Why are radiators always placed under windows?
157	Can we theoretically balance a perfectly symmetrical pencil on its one-atom tip?
158	If Earth had rings?
159	How can time dilation be symmetric?
160	Quantum Entanglement - Whats the big deal?
161	If we had a perfectly efficient computer and all the energy in the Milky-way available, what number could it count to?
162	Why does the LIGO observation disprove higher dimensions?
163	Why does nature favour the Laplacian?
164	What software programs are used to draw physics diagrams, and what are their relative merits?
165	Why do same/opposite electric charges repel/attract each other, respectively?
166	What conservation law corresponds to Lorentz boosts?
167	Why quantum mechanics?
168	Does a gun exert enough gravity on the bullet it fired to stop it?
169	Why does my wooden door disperse light into a rainbow color spectrum?
170	What is the relation between electromagnetic wave and photon?
171	Why is the $S_{z} =0$ state forbidden for photons?
172	Seeing something from only one angle means you have only seen (what?)% of its surface area at most?
173	Are Newtons laws of motion laws or definitions of force and mass?
174	Does juggling balls reduce the total weight of the juggler and balls?
175	Why does a remote car key work when held to your head/body?
176	Why does matter exist in 3 states (liquids, solid, gas)?
177	How did Einstein know the speed of light was constant?
178	Why does a billiard ball stop when it hits another billiard ball head on?
179	Am I attracting Pluto?
180	Why does a yellow object turn white under a yellow light? Shouldnt it turn yellow instead?
181	Why is a laserpointer able to erase a glow-in-the-dark sticker?
182	Can tin foil hats block anything?
183	Why is a $5-60 mph$ time slower than a $0-60 mph$ time for some automobiles?
184	Why do scientists think that all the laws of physics that apply in our galaxy apply in other galaxies?
185	Why do phones land face down?
186	What is a manifold?
187	Why cant $ i\hbar\frac{\partial}{\partial t}$ be considered the Hamiltonian operator?
188	How does this baby rattle work?
189	Superluminal neutrinos
190	Why do metals only glow red, yellow and white and not through the full range of the spectrum?
191	What is time, does it flow, and if so what defines its direction?
192	How exactly do you avoid fooling yourself?
193	Why are differential equations for fields in physics of order two?
194	Quantum Field Theory from a mathematical point of view
195	Why is light bent but not accelerated?
196	Why can Hiroshima be inhabited when Chernobyl cannot?
197	What makes running so much less energy-efficient than bicycling?
198	Why is it bad taste to have a dimensional quantity in the argument of a logarithm or exponential function?
199	What is spontaneous symmetry breaking in quantum systems?
200	Why does a full moon seem uniformly bright from earth, shouldnt it be dimmer at the border?
201	Why is information indestructible?
202	Why dont fluorescent lights produce shadows?
203	If you are vacuuming your carpet and you wrap the cord around your body do you become a magnet?
204	When I walk down the stairs where does my potential energy go?
205	What is more fundamental, fields or particles?
206	Why does rainwater form moving waves on the ground? Is there a name for this effect?
207	List of freely available physics books
208	In the earths crust, why is there far more uranium than gold?
209	Could a living planet alter its own trajectory only by changing its shape?
210	Classical and quantum anomalies
211	What causes the water in this fountain to reverse direction?
212	What is spin as it relates to subatomic particles?
213	If dark matter only interacts with gravity, why doesnt it all clump together in a single point?
214	Why doesnt water actually perfectly wet glass?
215	Can photons be detected without being absorbed?
216	Is there a symmetry associated to the conservation of information?
217	What does one second after big bang mean?
218	What happened to David John Candlin?
219	Why do travelling waves continue after amplitude sum = 0?
220	Will a hole cut into a metal disk expand or shrink when the disc is heated?
221	Why does public mains power use 50-60 Hz and 100-240 V?
222	How can magnets be used to pick up pieces of metal when the force from a magnetic field does no work?
223	How do laser tape measures work?
224	Why must a physical theory be mathematically self-consistent?
225	Why does a rubber band become a lighter color when stretched?
226	Does centrifugal force exist?
227	Why does water stop boiling immediately after turning off the heat?
228	Why does fire make very little sound?
229	Where does the extra kinetic energy come from in a gravitational slingshot?
230	What was the major discovery on gravitational waves made March 17th, 2014, in the BICEP2 experiment?
231	Why doesnt the Moon fall onto the Earth?
232	How and why do accelerating charges radiate electromagnetic radiation?
233	Visually stunning math concepts which are easy to explain
234	Is $\frac{\textrm{d}y}{\textrm{d}x}$ not a ratio?
235	How long will it take Marie to saw another board into 3 pieces?
236	Can I use my powers for good?
237	The staircase paradox, or why $\pi\ne4$
238	How to study math to really understand it and have a healthy lifestyle with free time?
239	Different methods to compute $\sum\limits_{k=1}^\infty \frac{1}{k^2}$ (Basel problem)
240	Whats an intuitive way to think about the determinant?
241	Does $\pi$ contain all possible number combinations?
242	Splitting a sandwich and not feeling deceived
243	What was the first bit of mathematics that made you realize that math is beautiful? (For childrens book)
244	Why is $1 - \frac{1}{1 - \frac{1}{1 - \ldots}}$ not real?
245	Why can you turn clothing right-side-out?
246	Examples of patterns that eventually fail
247	Mathematical difference between white and black notes in a piano
248	Do complex numbers really exist?
249	What are imaginary numbers?
250	How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?
251	Integral $\int_{-1}^1\frac1x\sqrt{\frac{1+x}{1-x}}\ln\left(\frac{2\,x^2+2\,x+1}{2\,x^2-2\,x+1}\right) \mathrm dx$
252	The Egg: Bizarre behavior of the roots of a family of polynomials.
253	Is this Batman equation for real?
254	Best Sets of Lecture Notes and Articles
255	My sons Sum of Some is beautiful! But what is the proof or explanation?
256	Proofs that every mathematician should know.
257	Why does $1+2+3+\cdots = -\frac{1}{12}$?
258	What is the intuitive relationship between SVD and PCA?
259	How can I evaluate $\sum_{n=0}^\infty(n+1)x^n$?
260	On familiarity (or How to avoid going down the Math Rabbit Hole?)
261	Fourier transform for dummies
262	The Ring Game on $K[x,y,z]$
263	Pedagogy: How to cure students of the law of universal linearity?
264	Find five positive integers whose reciprocals sum to $1$
265	Can every proof by contradiction also be shown without contradiction?
266	Obvious theorems that are actually false
267	Zero to the zero power – is $0^0=1$?
268	If $AB = I$ then $BA = I$
269	Calculating the length of the paper on a toilet paper roll
270	How can you prove that a function has no closed form integral?
271	A challenge by R. P. Feynman: give counter-intuitive theorems that can be translated into everyday language
272	Surprising identities / equations
273	Is it true that $0.999999999\ldots=1$?
274	Why dont we define imaginary numbers for every impossibility?
275	What is the importance of eigenvalues/eigenvectors?
276	Nice examples of groups which are not obviously groups
277	Multiple-choice question about the probability of a random answer to itself being correct
278	In Russian roulette, is it best to go first?
279	One question to know if the number is 1, 2 or 3
280	Why does this innovative method of subtraction from a third grader always work?
281	Intuition for the definition of the Gamma function?
282	Why can ALL quadratic equations be solved by the quadratic formula?
283	Math without pencil and paper
284	V.I. Arnold says Russian students cant solve this problem, but American students can -- why?
285	Really advanced techniques of integration (definite or indefinite)
286	Is mathematics one big tautology?
287	Help with a prime number spiral which turns 90 degrees at each prime
288	Is $10$ a magical number or I am missing something?
289	Funny identities
290	Cant argue with success? Looking for bad math that gets away with it
291	Is $7$ the only prime followed by a cube?
292	In the history of mathematics, has there ever been a mistake?
293	The Mathematics of Tetris
294	Given an infinite number of monkeys and an infinite amount of time, would one of them write Hamlet?
295	Why do mathematicians use single-letter variables?
296	How does one prove the determinant inequality $\det\left(6(A^3+B^3+C^3)+I_{n}\right)\ge 5^n\det(A^2+B^2+C^2)$?
297	Is a matrix multiplied with its transpose something special?
298	How discontinuous can a derivative be?
299	Too old to start math
300	Evaluate $ \int_{0}^{\frac{\pi}2}\frac1{(1+x^2)(1+\tan x)}\:\mathrm dx$
301	What is the maximum volume that can be contained by a sheet of paper?
302	Please explain the intuition behind the dual problem in optimization.
303	Evaluating the integral $\int_0^\infty \frac{\sin x} x \,\mathrm dx = \frac \pi 2$?
304	Norms Induced by Inner Products and the Parallelogram Law
305	Fun but serious mathematics books to gift advanced undergraduates.
306	Which answer in this list is the correct answer to this question?
307	What is the practical difference between a differential and a derivative?
308	Evaluating $\lim\limits_{n\to\infty} e^{-n} \sum\limits_{k=0}^{n} \frac{n^k}{k!}$
309	Does the square or the circle have the greater perimeter? A surprisingly hard problem for high schoolers
310	Can you answer my sons fourth-grade homework question: Which numbers are prime, have digits adding to ten and have a three in the tens place?
311	The Integral that Stumped Feynman?
312	In (relatively) simple words: What is an inverse limit?
313	What is the importance of the Collatz conjecture?
314	What are some examples of when Mathematics accidentally discovered something about the world?
315	Derivative of sigmoid function $\sigma (x) = \frac{1}{1+e^{-x}}$
316	Conjectures that have been disproved with extremely large counterexamples?
317	Best Fake Proofs? (A M.SE April Fools Day collection)
318	Any open subset of $\Bbb R$ is a countable union of disjoint open intervals
319	Why study Algebraic Geometry?
320	Why are rings called rings?
321	What is the result of $\infty - \infty$?
322	Integral Milking
323	A 1,400 years old approximation to the sine function by Mahabhaskariya of Bhaskara I
324	How to read a book in mathematics?
325	Why do we care about dual spaces?
326	What are some counter-intuitive results in mathematics that involve only finite objects?
327	How many fours are needed to represent numbers up to $N$?
328	Is there an elementary proof that $\sum \limits_{k=1}^n \frac1k$ is never an integer?
329	Your favourite application of the Baire Category Theorem
330	What books must every math undergraduate read?
331	Proving you *cant* make $2011$ out of $1,2,3,4$: nice twist on the usual
332	Does the open mapping theorem imply the Baire category theorem?
333	Optimizing response times of an ambulance corp: short-term versus average
334	Is there a 0-1 law for the theory of groups?
335	How can a piece of A4 paper be folded in exactly three equal parts?
336	Eigenvectors of real symmetric matrices are orthogonal
337	Do men or women have more brothers?
338	In simple English, what does it mean to be transcendental?
339	How to check if a point is inside a rectangle?
340	Good books and lecture notes about category theory.
341	Why does this matrix give the derivative of a function?
342	Is it faster to count to the infinite going one by one or two by two?
343	What are the Differences Between a Matrix and a Tensor?
344	How do I convince someone that $1+1=2$ may not necessarily be true?
345	How do I sell out with abstract algebra?
346	Why can a Venn diagram for $4+$ sets not be constructed using circles?
347	Identification of a quadrilateral as a trapezoid, rectangle, or square
348	Meaning of Rays in Polar Plot of Prime Numbers
349	What does $2^x$ really mean when $x$ is not an integer?
350	What do modern-day analysts actually do?
351	Proving $\int_{0}^{\infty} \mathrm{e}^{-x^2} dx = \frac{\sqrt \pi}{2}$
352	Is computer science a branch of mathematics?
353	What is the difference between linear and affine function
354	Which one result in mathematics has surprised you the most?
355	Books on Number Theory for Layman
356	Teaching myself differential topology and differential geometry
357	List of interesting math videos / documentaries
358	Exterior Derivative vs. Covariant Derivative vs. Lie Derivative
359	How to show $e^{e^{e^{79}}}$ is not an integer
360	Are $14$ and $21$ the only interesting numbers?
361	How could we define the factorial of a matrix?
362	When can you switch the order of limits?
363	List of Interesting Math Blogs
364	Generalizing $\int_{0}^{1} \frac{\arctan\sqrt{x^{2} + 2}}{\sqrt{x^{2} + 2}} \, \frac{\operatorname dx}{x^{2}+1} = \frac{5\pi^{2}}{96}$
365	How do we prove that something is unprovable?
366	How many sides does a circle have?
367	Whats the intuition behind Pythagoras theorem?
368	Why is compactness so important?
369	Can a coin with an unknown bias be treated as fair?
370	A Topology such that the continuous functions are exactly the polynomials
371	What is the geometric interpretation of the transpose?
372	Counterintuitive examples in probability
373	What is a good complex analysis textbook, barring Ahlforss?
374	What were some major mathematical breakthroughs in 2016?
375	How to intuitively understand eigenvalue and eigenvector?
376	Importance of Representation Theory
377	Advice to young mathematicians
378	Why cant differentiability be generalized as nicely as continuity?
379	How to define a bijection between $(0,1)$ and $(0,1]$?
380	Derivative of Softmax loss function
381	Some users are mind bogglingly skilled at integration. How did they get there?
382	How do people perform mental arithmetic for complicated expressions?
383	Can we ascertain that there exists an epimorphism $G\rightarrow H$?
384	What Does it Really Mean to Have Different Kinds of Infinities?
385	How do you revise material that you already half-know, without getting bored and demotivated?
386	Are there any series whose convergence is unknown?
387	When can a sum and integral be interchanged?
388	A math contest problem $\int_0^1\ln\left(1+\frac{\ln^2x}{4\,\pi^2}\right)\frac{\ln(1-x)}x \ \mathrm dx$
389	Symmetry of function defined by integral
390	Why $\sqrt{-1 \cdot {-1}} \neq \sqrt{-1}^2$?
391	Self-Contained Proof that $\sum\limits_{n=1}^{\infty} \frac1{n^p}$ Converges for $p > 1$
392	There are apparently $3072$ ways to draw this flower. But why?
393	Proving the identity $\sum_{k=1}^n {k^3} = \big(\sum_{k=1}^n k\big)^2$ without induction
394	Proof that the trace of a matrix is the sum of its eigenvalues
395	Limit of $L^p$ norm
396	Is there a categorical definition of submetry?
397	Deleting any digit yields a prime... is there a name for this?
398	Inverse of the sum of matrices
399	What is $dx$ in integration?
400	Is $2048$ the highest power of $2$ with all even digits (base ten)?
401	Why is Eulers Gamma function the best extension of the factorial function to the reals?
402	$L^p$ and $L^q$ space inclusion
403	Do we have negative prime numbers?
404	Why do people use it is easy to prove?
405	Taking Seats on a Plane
406	Why is $1^{\infty}$ considered to be an indeterminate form
407	Mathematical ideas that took long to define rigorously
408	Open problems in General Relativity
409	How far can one get in analysis without leaving $\mathbb{Q}$?
410	How can we sum up $\sin$ and $\cos$ series when the angles are in arithmetic progression?
411	Rational roots of polynomials
412	Lesser-known integration tricks
413	A variation of Fermats little theorem in the form $a^{n-d}\equiv a$ (mod $p$).
414	Is there a homology theory that counts connected components of a space?
415	Prove that $\gcd(a^n - 1, a^m - 1) = a^{\gcd(n, m)} - 1$
416	An Introduction to Tensors
417	Transpose of inverse vs inverse of transpose
418	How to prove Eulers formula: $e^{i\varphi}=\cos(\varphi) +i\sin(\varphi)$?
419	Intuition behind Matrix Multiplication
420	Striking applications of integration by parts
421	Why is the Penrose triangle impossible?
422	Software for drawing geometry diagrams
423	How to prove: if $a,b \in \mathbb N$, then $a^{1/b}$ is an integer or an irrational number?
424	Examples of mathematical discoveries which were kept as a secret
425	What properties of busy beaver numbers are computable?
426	What happens when we (incorrectly) make improper fractions proper again?
427	Can you provide me historical examples of pure mathematics becoming useful?
428	What are the most overpowered theorems in mathematics?
429	Do we know if there exist true mathematical statements that can not be proven?
430	Is there any integral for the Golden Ratio?
431	Using proof by contradiction vs proof of the contrapositive
432	Evaluate $\int_0^1 \frac{\log \left( 1+x^{2+\sqrt{3}}\right)}{1+x}\mathrm dx$
433	Induction on Real Numbers
434	Proof that ${\left(\pi^\pi\right)}^{\pi^\pi}$ (and now $\pi^{\left(\pi^{\pi^\pi}\right)}$) is a noninteger.
435	The Hole in One Pizza
436	Proof of $\frac{1}{e^{\pi}+1}+\frac{3}{e^{3\pi}+1}+\frac{5}{e^{5\pi}+1}+\ldots=\frac{1}{24}$
437	What functions can be made continuous by mixing up their domain?
438	Is there a general formula for solving 4th degree equations (quartic)?
439	Discontinuous derivative.
440	Monty hall problem extended.
441	The sum of an uncountable number of positive numbers
442	Is Apple ipad / tablet good for mathematics students?
443	Stopping the Will I need this for the test question
444	Are there any open mathematical puzzles?
445	Find a real function $f:\mathbb{R}\to\mathbb{R}$ such that $f(f(x)) = -x$?
446	How to distinguish between walking on a sphere and walking on a torus?
447	Is there a quick proof as to why the vector space of $\mathbb{R}$ over $\mathbb{Q}$ is infinite-dimensional?
448	Is there another simpler method to solve this elementary school math problem?
449	Most ambiguous and inconsistent phrases and notations in maths
450	Why does factoring eliminate a hole in the limit?
451	Whats the point in being a skeptical learner
452	Good book for self study of a First Course in Real Analysis
453	Overview of basic results about images and preimages
454	How to determine with certainty that a function has no elementary antiderivative?
455	What actually is a polynomial?
456	Sum of random decreasing numbers between 0 and 1: does it converge??
457	Are there real-life relations which are symmetric and reflexive but not transitive?
458	Calculate Rotation Matrix to align Vector A to Vector B in 3d?
459	Whats new in higher dimensions?
460	How do you describe your mathematical research in laymans terms?
461	Pythagorean triples that survive Eulers totient function
462	Whats the significance of Tates thesis?
463	What is the difference between singular value and eigenvalue?
464	Intuition of the meaning of homology groups
465	Why does the series $\sum_{n=1}^\infty\frac1n$ not converge?
466	Why does an argument similiar to 0.999...=1 show 999...=-1?
467	Does a cubic matrix exist?
468	Is the following matrix invertible?
469	Do most mathematicians know most topics in mathematics?
470	Slice of pizza with no crust
471	Has lack of mathematical rigour killed anybody before?
472	Alternative notation for exponents, logs and roots?
473	Math and mental fatigue
474	What is the Riemann-Zeta function?
475	Why do both sine and cosine exist?
476	What is the best book to learn probability?
477	The square roots of different primes are linearly independent over the field of rationals
478	Can someone explain the math behind tessellation?
479	Where to start learning Linear Algebra?
480	Intuitively, what is the difference between Eigendecomposition and Singular Value Decomposition?
481	Looking for an intuitive explanation why the row rank is equal to the column rank for a matrix
482	Example of infinite field of characteristic $p\neq 0$
483	Is non-standard analysis worth learning?
484	Connection between Fourier transform and Taylor series
485	Are we allowed to compare infinities?
486	Online tool for making graphs (vertices and edges)?
487	Whats 4 times more likely than 80%?
488	Simple theorems that are instances of deep mathematics
489	Do Arithmetic Mean and Geometric Mean of Prime Numbers converge?
490	Partial derivative in gradient descent for two variables
491	Apparently sometimes $1/2 < 1/4$?
492	Is the product of two Gaussian random variables also a Gaussian?
493	Intuitive explanation of entropy
494	The Best of Dover Books (a.k.a the best cheap mathematical texts)
495	Are mathematical articles on Wikipedia reliable?
496	What are the differences between rings, groups, and fields?
497	Why do units (from physics) behave like numbers?
498	Studying Euclidean geometry using hyperbolic criteria
499	Examples of bijective map from $\mathbb{R}^3\rightarrow \mathbb{R}$
500	Identification of a curious function
501	What is the difference between regression and classification?
502	How to put 9 pigs into 4 pens so that there are an odd number of pigs in each pen?
503	How do you respond to I was always bad at math?
504	What are the numbers before and after the decimal point referred to in mathematics?
505	Can you explain the Axiom of choice in simple terms?
506	Why do we use the word scalar and not number in Linear Algebra?
507	What is the difference between Fourier series and Fourier transformation?
508	What is the difference between a point and a vector?
509	The direct sum $\oplus$ versus the cartesian product $\times$
510	Is the blue area greater than the red area?
511	Does $R[x] \cong S[x]$ imply $R \cong S$?
512	Why does mathematical convention deal so ineptly with multisets?
513	List of interesting math podcasts?
514	Can you raise a number to an irrational exponent?
515	Examples of mathematical results discovered late
516	$\pi$ in arbitrary metric spaces
517	Proving an alternating Euler sum: $\sum_{k=1}^{\infty} \frac{(-1)^{k+1} H_k}{k} = \frac{1}{2} \zeta(2) - \frac{1}{2} \log^2 2$
518	Is there any mathematical reason for this digit-repetition-show?
519	Visually deceptive proofs which are mathematically wrong
520	Best book of topology for beginner?
521	Can someone explain Gödels incompleteness theorems in layman terms?
522	Why is $1$ not a prime number?
523	Studying for the Putnam Exam
524	Intuitive interpretation of the Laplacian
525	what is expected from a PhD student?
526	Why is the eigenvector of a covariance matrix equal to a principal component?
527	Sum of First $n$ Squares Equals $\frac{n(n+1)(2n+1)}{6}$
528	Is it possible for a function to be in $L^p$ for only one $p$?
529	What are some examples of notation that really improved mathematics?
530	Classification of prime ideals of $\mathbb{Z}[X]$
531	Division by $0$
532	Application of Hilberts basis theorem in representation theory
533	Is $0$ a natural number?
534	Why is negative times negative = positive?
535	On Ph.D. Qualifying Exams
536	Elementary proof that $\mathbb{R}^n$ is not homeomorphic to $\mathbb{R}^m$
537	What are some examples of a mathematical result being counterintuitive?
538	Can you be 1/12th Cherokee?
539	Why did mathematicians take Russells paradox seriously?
540	Values of $\sum_{n=0}^\infty x^n$ and $\sum_{n=0}^N x^n$
541	How to find ${\large\int}_0^1\frac{\ln^3(1+x)\ln x}x\mathrm dx$
542	What is the probability that a point chosen randomly from inside an equilateral triangle is closer to the center than to any of the edges?
543	Why is learning modern algebraic geometry so complicated?
544	What should be the intuition when working with compactness?
545	Motivation of irrationality measure
546	Show that the determinant of $A$ is equal to the product of its eigenvalues
547	The median minimizes the sum of absolute deviations (the $ {\ell}_{1} $ norm)
548	Why is gradient the direction of steepest ascent?
549	Learning Lambda Calculus
550	Is there a function that grows faster than exponentially but slower than a factorial?
551	How to find solutions of linear Diophantine ax + by = c?
552	What is category theory useful for?
553	Are half of all numbers odd?
554	Can $x^{x^{x^x}}$ be a rational number?
555	Prove that $C\exp(x)$ is the only set of functions for which $f(x) = f(x)$
556	Are if and iff interchangeable in definitions?
557	Is there an integral that proves $\pi > 333/106$?
558	Past open problems with sudden and easy-to-understand solutions
559	How to prove $\int_0^1\tan^{-1}\left[\frac{\tanh^{-1}x-\tan^{-1}x}{\pi+\tanh^{-1}x-\tan^{-1}x}\right]\frac{dx}{x}=\frac{\pi}{8}\ln\frac{\pi^2}{8}?$
560	What remains in a students mind
561	Proof $1+2+3+4+\cdots+n = \frac{n\times(n+1)}2$
562	Why is $\infty \cdot 0$ not clearly equal to $0$?
563	What are good books to learn graph theory?
564	Can an irrational number raised to an irrational power be rational?
565	Advantages of Mathematics competition/olympiad students in Mathematical Research
566	Whats the difference between predicate and propositional logic?
567	How can I find the surface area of a normal chicken egg?
568	Why does LHopitals rule fail in calculating $\lim_{x \to \infty} \frac{x}{x+\sin(x)}$?
569	Why study linear algebra?
570	Why is integration so much harder than differentiation?
571	Why is $\cos (90)=-0.4$ in WebGL?
572	Why “characteristic zero” and not “infinite characteristic”?
573	Why are the solutions of polynomial equations so unconstrained over the quaternions?
574	Making Friends around a Circular Table
575	Is There An Injective Cubic Polynomial $\mathbb Z^2 \rightarrow \mathbb Z$?
576	Real life applications of Topology
577	Whats your favorite proof accessible to a general audience?
578	Pullback and Pushforward Isomorphism of Sheaves
579	Physical meaning of the null space of a matrix
580	How do you explain to a 5th grader why division by zero is meaningless?
581	Overview of basic facts about Cauchy functional equation
582	Is 10 closer to infinity than 1?
583	Examples of problems that are easier in the infinite case than in the finite case.
584	Help find hard integrals that evaluate to $59$?
585	Is the inverse of a symmetric matrix also symmetric?
586	When to learn category theory?
587	In classical logic, why is $(p\Rightarrow q)$ True if both $p$ and $q$ are False?
588	Modular exponentiation by hand ($a^b\bmod c$)
589	How were old-school mathematics graphics created?
590	Infiniteness of non-twin primes.
591	probability $2/4$ vs $3/6$
592	Continuous projections on $\ell_1$ with norm $>1$
593	Is there a characterization of groups with the property $\forall N\unlhd G,\:\exists H\leq G\text{ s.t. }H\cong G/N$?
594	All real numbers in $[0,2]$ can be represented as $\sqrt{2 \pm \sqrt{2 \pm \sqrt{2 \pm \dots}}}$
595	Olympiad Inequality $\sum\limits_{cyc} \frac{x^4}{8x^3+5y^3} \geqslant \frac{x+y+z}{13}$
596	What is the difference between independent and mutually exclusive events?
597	What is the Jacobian matrix?
598	If squaring a number means multiplying that number with itself then shouldnt taking square root of a number mean to divide a number by itself?
599	Is there a known well ordering of the reals?
600	Intuition behind Conditional Expectation
601	Is there an inverted dot product?
602	Find the average of $\sin^{100} (x)$ in 5 minutes?
603	How to find the Galois group of a polynomial?
604	Strategies for Effective Self-Study
605	What did Alan Turing mean when he said he didnt fully understand dy/dx?
606	Is there a domain larger than (i.e., a supserset of) the complex number domain?
607	Motivation for the rigour of real analysis
608	Probability that a stick randomly broken in five places can form a tetrahedron
609	The deep reason why $\int \frac{1}{x}\operatorname{d}x$ is a transcendental function ($\log$)
610	Expected time to roll all 1 through 6 on a die
611	Proofs of AM-GM inequality
612	The math behind Warren Buffetts famous rule – never lose money
613	Compute $\int_0^{\pi/4}\frac{(1-x^2)\ln(1+x^2)+(1+x^2)-(1-x^2)\ln(1-x^2)}{(1-x^4)(1+x^2)} x\exp(\frac{x^2-1}{x^2+1}) dx$
614	derivative of cost function for Logistic Regression
615	Construction of a Borel set with positive but not full measure in each interval
616	Are the proofs by contradiction weaker than other proofs?
617	Why are There No Triernions (3-dimensional analogue of complex numbers / quaternions)?
618	What parts of a pure mathematics undergraduate curriculum have been discovered since $1964?$
619	Is black hole pattern possible in Conways Game of Life that eats/clears everything?
620	A multiplication algorithm found in a book by Paul Erdős: how does it work?
621	Are all limits solvable without LHôpital Rule or Series Expansion
622	$n!$ is never a perfect square if $n\geq2$. Is there a proof of this that doesnt use Chebyshevs theorem?
623	Convergence of $\sum_{n=1}^{\infty} \frac{\sin(n!)}{n}$
624	When is matrix multiplication commutative?
625	What is the difference and relationship between the binomial and Bernoulli distributions?
626	Is infinity a number?
627	Am I just not smart enough?
628	What is the smallest unknown natural number?
629	Is there a positive definition for irrational numbers?
630	Solving Special Function Equations Using Lie Symmetries
631	Gross-Zagier formulae outside of number theory
632	Why is the derivative of a circles area its perimeter (and similarly for spheres)?
633	Getting better at proofs
634	Mathematical equivalent of Feynmans Lectures on Physics?
635	How often does it happen that the oldest person alive dies?
636	Do mathematicians, in the end, always agree?
637	Can an infinite sum of irrational numbers be rational?
638	Unexpected examples of natural logarithm
639	What are the Axiom of Choice and Axiom of Determinacy?
640	Least prime of the form $38^n+31$
641	Different ways to prove there are infinitely many primes?
642	Can you give an example of a complex math problem that is easy to solve?
643	Proof of Frullanis theorem
644	More than 99% of groups of order less than 2000 are of order 1024?
645	Find all functions $f$ such that if $a+b$ is a square, then $f(a)+f(b)$ is a square
646	Does a four-variable analog of the Hall-Witt identity exist?
647	How do I get the square root of a complex number?
648	Prove that $||x|-|y||\le |x-y|$
649	Prove that simultaneously diagonalizable matrices commute
650	Could someone explain conditional independence?
651	Good Book On Combinatorics
652	A good way to retain mathematical understanding?
653	Why is it important for a matrix to be square?
654	Are there real world applications of finite group theory?
655	Why cant calculus be done on the rational numbers?
656	Why is there no remainder in multiplication
657	What are the issues in modern set theory?
658	What makes a theorem fundamental?
659	Why is an average of an average usually incorrect?
660	Finding a primitive root of a prime number
661	Do factorials really grow faster than exponential functions?
662	What exactly is the difference between a derivative and a total derivative?
663	Nice proofs of $\zeta(4) = \frac{\pi^4}{90}$?
664	Why, historically, do we multiply matrices as we do?
665	Why do we still do symbolic math?
666	Fastest way to meet, without communication, on a sphere?
667	Grothendieck s question - any update?
668	How to sum this series for $\pi/2$ directly?
669	In a family with two children, what are the chances, if one of the children is a girl, that both children are girls?
670	Can someone clearly explain about the lim sup and lim inf?
671	How can I understand and prove the sum and difference formulas in trigonometry?
672	Is zero odd or even?
673	Continuity of the roots of a polynomial in terms of its coefficients
674	In calculus, which questions can the naive ask that the learned cannot answer?
675	Why are mathematical proofs that rely on computers controversial?
676	Getting Students to Not Fear Confusion
677	Topology: The Board Game
678	Fibonacci number that ends with 2014 zeros?
679	What is the smallest number of $45^\circ-60^\circ-75^\circ$ triangles that a square can be divided into?
680	Generalization of Liouvilles theorem
681	Complete course of self-study
682	Motivation for Ramanujans mysterious $\pi$ formula
683	What is the most unusual proof you know that $\sqrt{2}$ is irrational?
684	How do we know an $ \aleph_1 $ exists at all?
685	Connected metric spaces with disjoint open balls
686	Why is the volume of a sphere $\frac{4}{3}\pi r^3$?
687	Incremental averageing
688	How to show that a set of discontinuous points of an increasing function is at most countable
689	If I flip a coin 1000 times in a row and it lands on heads all 1000 times, what is the probability that its an unfair coin?
690	What made you choose your research field?
691	How Do You Actually Do Your Mathematics?
692	Is this continuous analogue to the AM–GM inequality true?
693	Open mathematical questions for which we really, really have no idea what the answer is
694	Is the derivative the natural logarithm of the left-shift?
695	Has Prof. Otelbaev shown existence of strong solutions for Navier-Stokes equations?
696	lim sup and lim inf of sequence of sets.
697	Why is it hard to prove whether $\pi+e$ is an irrational number?
698	How do you go about learning mathematics?
699	Is $[0,1]$ a countable disjoint union of closed sets?
700	Chatting about mathematics (with real-time LaTeX rendering)
701	Calculating the integral $\int_0^\infty \frac{\cos x}{1+x^2}\, \mathrm{d}x$ without using complex analysis
702	Finding the limit of $\frac {n}{\sqrt[n]{n!}}$
703	What is the single most influential book every mathematician should read?
704	Logic puzzle: Which octopus is telling the truth?
705	Why is a geometric progression called so?
706	Why, intuitively, is the order reversed when taking the transpose of the product?
707	Prove the theorem on analytic geometry in the picture.
708	Good Physical Demonstrations of Abstract Mathematics
709	Can I think of Algebra like this?
710	Ways to evaluate $\int \sec \theta \, \mathrm d \theta$
711	Closed form for $ \int_0^\infty {\frac{{{x^n}}}{{1 + {x^m}}}dx }$
712	Does this property characterize a space as Hausdorff?
713	All polynomials with no natural roots and integer coefficients such that $\phi(n)|\phi(P(n))$
714	How to prove that eigenvectors from different eigenvalues are linearly independent
715	Lebesgue integral basics
716	Why rationalize the denominator?
717	Mathematicians ahead of their time?
718	Are all algebraic integers with absolute value 1 roots of unity?
719	Can we remove any prime number with this strange process?
720	Produce an explicit bijection between rationals and naturals?
721	Is math built on assumptions?
722	Riddles that can be solved by meta-assumptions
723	Why are vector spaces not isomorphic to their duals?
724	What are some examples of mathematics that had unintended useful applications much later?
725	Division by $0$ and its restrictions
726	Theorems with an extraordinary exception or a small number of sporadic exceptions
727	True or false? $x^2\ne x\implies x\ne 1$
728	$\int_{-\infty}^{+\infty} e^{-x^2} dx$ with complex analysis
729	An integral involving Airy functions $\int_0^\infty\frac{x^p}{\operatorname{Ai}^2 x + \operatorname{Bi}^2 x}\mathrm dx$
730	Does notation ever become easier?
731	Mathematician vs. Computer: A Game
732	Non-textbook Math book recommendation to read to my kids
733	Cardioid in coffee mug?
734	Direct proof that the wedge product preserves integral cohomology classes?
735	How did Hermite calculate $e^{\pi\sqrt{163}}$ in 1859?
736	What does it mean to have a determinant equal to zero?
737	Why is the volume of a cone one third of the volume of a cylinder?
738	Dont see the point of the Fundamental Theorem of Calculus.
739	Comparing $\pi^e$ and $e^\pi$ without calculating them
740	Is Bayes Theorem really that interesting?
741	Unconventional mathematics books
742	Does LHôpitals work the other way?
743	Geometric interpretation of the Riemann-Roch for curves
744	Whats the difference between theorem, lemma and corollary?
745	Unusual mathematical terms
746	Is infinity an odd or even number?
747	How do you find the center of a circle with a pencil and a book?
748	Using we have in maths papers
749	How to learn from proofs?
750	What are Some Tricks to Remember Fatous Lemma?
751	Why dont analysts do category theory?
752	Defining a manifold without reference to the reals
753	Does a non-trivial solution exist for $f(x)=f(f(x))$?
754	A community project: prove (or disprove) that $\sum_{n\geq 1}\frac{\sin(2^n)}{n}$ is convergent
755	A real number $x$ such that $x^n$ and $(x+1)^n$ are rational is itself rational
756	Expectation of the maximum of gaussian random variables
757	Simplest or nicest proof that $1+x \le e^x$
758	What would base $1$ be?
759	Should I put number combinations like 1111111 onto my lottery ticket?
760	Continuous bijection from $(0,1)$ to $[0,1]$
761	How is a system of axioms different from a system of beliefs?
762	Why cant you add apples and oranges, but you can multiply and divide them?
763	How can adding an infinite number of rationals yield an irrational number?
764	Example of a very simple math statement in old literature which is (verbatim) a pain to understand
765	Whats the largest possible volume of a taco, and how do I make one that big?
766	Limit of sequence in which each term is defined by the average of preceding two terms
767	Why are all the interesting constants so small?
768	Help me put these enormous numbers in order: googol, googol-plex-bang, googol-stack and so on
769	$4494410$ and friends
770	A semigroup $X$ is a group iff for every $g\in X$, $\exists! x\in X$ such that $gxg = g$
771	Arithmetic-geometric mean of 3 numbers
772	Geometric way to view the truncated braid groups?
773	Prove $\operatorname{rank}A^TA=\operatorname{rank}A$ for any $A\in M_{m \times n}$
774	How to find a general sum formula for the series: 5+55+555+5555+.....?
775	What is the difference between a class and a set?
776	Why is $\frac{987654321}{123456789} = 8.0000000729?!$
777	The Langlands program for beginners
778	What makes elementary functions elementary?
779	Why would I want to multiply two polynomials?
780	If $x$, $y$, $x+y$, and $x-y$ are prime numbers, what is their sum?
781	Mathematicians Tensors vs. Physicists Tensors
782	Is the determinant that shows up accidental?
783	Given a die, what is the probability that the second roll of a die will be less than the first roll?
784	Why is the set of all sets a paradox, in Laymans terms?
785	Evaluate the integral: $\int_{0}^{1} \frac{\ln(x+1)}{x^2+1} \mathrm dx$
786	What seemingly innocuous results in mathematics require advanced proofs?
787	Prove $\left(\frac{2}{5}\right)^{\frac{2}{5}}<\ln{2}$
788	How to convince a math teacher of this simple and obvious fact?
789	What kind of symmetry is the symmetric group about?
790	What are good math habits that have improved your mathematical practice?$ $
791	math fallacy problem: $-1= (-1)^3 = (-1)^{6/2} = \sqrt{(-1)^6}= 1$?
792	Cover of Gödel, Escher, Bach
793	Problems that become easier in a more general form
794	How prove this nice limit $\lim\limits_{n\to\infty}\frac{a_{n}}{n}=\frac{12}{\log{432}}$
795	When does a sequence of rotated-and-circumscribed rectangles converge to a square?
796	Why is the area under a curve the integral?
797	Good 1st PDE book for self study
798	Importance of matrix rank
799	Much less than, what does that mean?
800	Simple beautiful math proof
801	Anecdotes about famous mathematicians or physicists
802	Why do bell curves appear everywhere?
803	What are the differences between class, set, family, and collection?
804	What is the solution to Nashs problem presented in A Beautiful Mind?
805	Factorial and exponential dual identities
806	The pepperoni pizza problem
807	How to evaluate $\int_{0}^{\infty} \frac{x^{-\mathfrak{i}a}}{x^2+bx+1} \,\mathrm{d}x$ using complex analysis?
808	A Case Against the Math Gene
809	Complexity class of comparison of power towers
810	Does $\lfloor \sqrt{p} \rfloor$ generate all natural numbers?
811	Pointwise vs. Uniform Convergence
812	What is the algebraic intuition behind Vieta jumping in IMO1988 Problem 6?
813	GRE Subject Test - Past Papers, Books, Advice
814	Can the golden ratio accurately be expressed in terms of $e$ and $\pi$
815	How do you explain the concept of logarithm to a five year old?
816	If $f_k \to f$ a.e. and the $L^p$ norms converge, then $f_k \to f$ in $L^p$
817	What is a real-world metaphor for irrational numbers?
818	Intuitive explanation of Cauchys Integral Formula in Complex Analysis
819	Why should I believe in weak solutions to PDEs?
820	Explain homotopy to me
821	Prove elementarily that $\sqrt[n+1] {(n+1)!} - \sqrt[n] {n!}$ is strictly decreasing
822	Root Calculation by Hand
823	What does the dot product of two vectors represent?
824	Whats the difference between simple induction and strong induction?
825	What is the most elegant proof of the Pythagorean theorem?
826	Is the vector cross product only defined for 3D?
827	Best Maths Books for Non-Mathematicians
828	Self-studying real analysis — Tao or Rudin?
829	What are differences between affine space and vector space?
830	If $(a_n)\subset[0,\infty)$ is non-increasing and $\sum a_n<\infty$, then $\lim{n a_n} = 0$
831	Is arrow notation for vectors not mathematically mature?
832	I roll a die repeatedly until I get 6, and then count the number of 3s I got. Whats my expected number of 3s?
833	What is the difference between a Hamel basis and a Schauder basis?
834	Is there any conjecture that has been proved to be solvable/provable but whose direct solution/proof is not yet known?
835	Results that came out of nowhere.
836	Can the product of infinitely many elements from $\mathbb Q$ be irrational?
837	Divisibility by 7 rule, and Congruence Arithmetic Laws
838	Can you make a sphere out of a plane?
839	Cutting sticks puzzle
840	The Right Triangle Game
841	Geometric interpretation of $\det(A^T) = \det(A)$
842	How to prove that exponential grows faster than polynomial?
843	Alternative proof that $(a^2+b^2)/(ab+1)$ is a square when its an integer
844	Good book for self study of functional analysis
845	If $S$ is an infinite $\sigma$ algebra on $X$ then $S$ is not countable
846	$x^y = y^x$ for integers $x$ and $y$
847	100 blue-eyed islanders puzzle: 3 questions
848	Surprise exam paradox?
849	Demystify integration of $\int \frac{1}{x} \mathrm dx$
850	Your favourite maths puzzles
851	Number of simple edge-disjoint paths needed to cover a planar graph
852	Good abstract algebra books for self study
853	Does convergence in $L^p$ imply convergence almost everywhere?
854	Is there any difference between mapping and function?
855	Normal subgroup of prime index
856	Implies ($\Rightarrow$) vs. Entails ($\models$) vs. Provable ($\vdash$)
857	Learning mathematics as if an absolute beginner?
858	Why did no student correctly find a pair of $2\times 2$ matrices with the same determinant and trace that are not similar?
859	Will it become impossible to learn math?
860	Should an undergrad accept that some things dont make sense, or study the foundation of mathematics to resolve this?
861	Is $0! = 1$ because there is only one way to do nothing?
862	Conjecture $\int_0^1\frac{\mathrm dx}{\sqrt{1-x}\ \sqrt[4]x\ \sqrt[4]{2-x\,\sqrt3}}\stackrel?=\frac{2\,\sqrt2}{3\,\sqrt[8]3}\pi$
863	Why are groups more important than semigroups?
864	Can someone explain these strange properties of $10, 11, 12$ and $13$?
865	What is the best book for studying discrete mathematics?
866	Why cant you square both sides of an equation?
867	For any prime $p > 3$, why is $p^2-1$ always divisible by 24?
868	Is the notorious $n^2 + n + 41$ prime generator the last of its type?
869	Construct a function which is continuous in $[1,5]$ but not differentiable at $2, 3, 4$
870	Easy math proofs or visual examples to make high school students enthusiastic about math
871	Why do we define quotient groups for normal subgroups only?
872	Formal proof for $(-1) \times (-1) = 1$
873	Mathematically, why was the Enigma machine so hard to crack?
874	Is it possible to represent every huge number in abbreviated form?
875	$1=2$ | Continued fraction fallacy
876	How is a group made up of simple groups?
877	Cute Determinant Question
878	Modelling the Moving Sofa
879	Graph theoretic proof: For six irrational numbers, there are three among them such that the sum of any two of them is irrational.
880	Contest problem: Show $\sum_{n = 1}^\infty \frac{n^2a_n}{(a_1+\cdots+a_n)^2}0$, $\sum_{n = 1}^\infty \frac{1}{a_n}<\infty$
881	Proof of every convex function is continuous
882	Are calculus and real analysis the same thing?
883	A goat tied to a corner of a rectangle
884	Predicting Real Numbers
885	Why is abuse of notation tolerated?
886	Why are gauge integrals not more popular?
887	Do numbers get worse than transcendental?
888	Whats so special about standard deviation?
889	What concept does an open set axiomatise?
890	Would you ever stop rolling the die?
891	Geometric & Intuitive Meaning of $SL(2,R)$, $SU(2)$, etc... & Representation Theory of Special Functions
892	References for multivariable calculus
893	When is the closure of an open ball equal to the closed ball?
894	Can manholes be made in other shapes than circles, that prevent the cover from being able to fall down its own hole?
895	In what sense are math axioms true?
896	Identity for convolution of central binomial coefficients: $\sum\limits_{k=0}^n \binom{2k}{k}\binom{2(n-k)}{n-k}=2^{2n}$
897	Compute $\int \frac{\sin(x)}{\sin(x)+\cos(x)}\mathrm dx$
898	What are some conceptualizations that work in mathematics but are not strictly true?
899	Why do mathematicians sometimes assume famous conjectures in their research?
900	Where are the axioms?
901	How to prove that $\frac{\zeta(2) }{2}+\frac{\zeta (4)}{2^3}+\frac{\zeta (6)}{2^5}+\frac{\zeta (8)}{2^7}+\cdots=1$?
902	How do we know that Cantors diagonalization isnt creating a different decimal of the same number?
903	In categorical terms, why is there no canonical isomorphism from a finite dimensional vector space to its dual?
904	Determining information in minimum trials (combinatorics problem)
905	What is the term for a factorial type operation, but with summation instead of products?
906	Difference between gradient and Jacobian
907	Why does Turn! Turn! Turn! equal 241217.524881?
908	Is there a size of rectangle that retains its ratio when its folded in half?
909	What is ultrafinitism and why do people believe it?
910	Decidability of the Riemann Hypothesis vs. the Goldbach Conjecture
911	Intuition in algebra?
912	A continuous, nowhere differentiable but invertible function?
913	Conjecture $\int_0^1\frac{dx}{\sqrt[3]x\,\sqrt[6]{1-x}\,\sqrt{1-x\left(\sqrt{6}\sqrt{12+7\sqrt3}-3\sqrt3-6\right)^2}}=\frac\pi9(3+\sqrt2\sqrt[4]{27})$
914	Can someone explain this integration trick for log-sine integrals?
915	Polynomials such that roots=coefficients
916	Does $X\times S^1\cong Y\times S^1$ imply that $X\times\mathbb R\cong Y\times\mathbb R$?
917	Do groups, rings and fields have practical applications in CS? If so, what are some?
918	What is special about the numbers 9801, 998001, 99980001 ..?
919	How does Cantors diagonal argument work?
920	Proof of $\int_0^\infty \left(\frac{\sin x}{x}\right)^2 \mathrm dx=\frac{\pi}{2}.$
921	Why is a circle in a plane surrounded by 6 other circles?
922	Expected number of unpecked chicks - NYT article
923	Whats the difference between $\mathbb{R}^2$ and the complex plane?
924	What is your favorite application of the Pigeonhole Principle?
925	Is mathematics just a bunch of nested empty sets?
926	Easy example why complex numbers are cool
927	Why is the construction of the real numbers important?
928	Any rectangular shape on a calculator numpad when divided by 11 gives an integer. Why?
929	Calculating the volume of a restaurant take-away box that is circular on the bottom and square on the top
930	Paul Erdoss Two-Line Functional Analysis Proof
931	Numbers $n$ such that the digit sum of $n^2$ is a square
932	How to solve these two simultaneous divisibilities : $n+1\mid m^2+1$ and $m+1\mid n^2+1$
933	Do most numbers have exactly $3$ prime factors?
934	Can a row of five equilateral triangles tile a big equilateral triangle?
935	Variance of sample variance?
936	Union of two vector subspaces not a subspace?
937	Probability density function vs. probability mass function
938	Determinant of a non-square matrix
939	What is a simple example of an unprovable statement?
940	Mathematical precise definition of a PDE being elliptic, parabolic or hyperbolic
941	Does commutativity imply Associativity?
942	What is the Tor functor?
943	100 Soldiers riddle
944	Why does Friedberg say that the role of the determinant is less central than in former times?
945	Is Lagranges theorem the most basic result in finite group theory?
946	Is $\sqrt {2 \sqrt {3 \sqrt {4 \ldots}}}$ algebraic or transcendental?
947	$6!\cdot 7!=10!$. Is there a natural bijection between $S_6\times S_7$ and $S_{10}$?
948	Show that the set of all finite subsets of $\mathbb{N}$ is countable.
949	$X$ is Hausdorff if and only if the diagonal of $X\times X$ is closed
950	Why are rotational matrices not commutative?
951	How to use the Extended Euclidean Algorithm manually?
952	How do I prove that $x^p-x+a$ is irreducible in a field with $p$ elements when $a\neq 0$?
953	What are some interpretations of Von Neumanns quote?
954	Why does the Mandelbrot set contain (slightly deformed) copies of itself?
955	If $a+b=1$ then $a^{4b^2}+b^{4a^2}\leq1$
956	General request for a book on mathematical history, for a VERY advanced reader.
957	Terence Tao–type books in other fields?
958	Alice and Bob play the determinant game
959	Is there a definitive guide to speaking mathematics?
960	$\frac{1}{n}$ as a difference of Egyptian fractions with all denominators $<n$
961	What are the practical applications of the Taylor Series?
962	Expected Number of Coin Tosses to Get Five Consecutive Heads
963	Understanding of the theorem that all norms are equivalent in finite dimensional vector spaces
964	Why is $e^{\pi \sqrt{163}}$ almost an integer?
965	$\sqrt{c+\sqrt{c+\sqrt{c+\cdots}}}$, or the limit of the sequence $x_{n+1} = \sqrt{c+x_n}$
966	Does mathematics require axioms?
967	The myth of no prime formula?
968	What is Bra and Ket notation and how does it relate to Hilbert spaces?
969	Intuitive meaning of Exact Sequence
970	Whats so natural about the base of natural logarithms?
971	What does surface area of a sphere actually mean (in terms of elementary school mathematics)?
972	The closed form of $\int_0^{\pi/4}\frac{\log(1-x) \tan^2(x)}{1-x\tan^2(x)} \ dx$
973	Can one deduce Liouvilles theorem (in complex analysis) from the non-emptiness of spectra in complex Banach algebras?
974	How to get a reflection vector?
975	Prove that $i^i$ is a real number
976	Is there a bijective map from $(0,1)$ to $\mathbb{R}$?
977	Is $\mathbf{Q}(\sqrt{2}, \sqrt{3}) = \mathbf{Q}(\sqrt{2}+\sqrt{3})$?
978	Cardinality of set of real continuous functions
979	A and B disjoint, A compact, and B closed implies there is positive distance between both sets
980	Why is a full turn of the circle 360°? Why not any other number?
981	Is there any easy way to understand the definition of Gaussian Curvature?
982	Are all infinities equal?
983	How to generate a random number between 1 and 10 with a six-sided die?
984	What is $\gcd(0,0)$?
985	In Linear Algebra, what is a vector?
986	Why isnt reflexivity redundant in the definition of equivalence relation?
987	Do you prove all theorems whilst studying?
988	Are all mathematicians human calculators?
989	Compute $ \lim\limits_{n \to \infty }\sin \sin \dots\sin n$
990	Does mathematics become circular at the bottom? What is at the bottom of mathematics?
991	linear algebra over a division ring vs. over a field
992	Why is compactness in logic called compactness?
993	20 circles in the plane, all passing through the origin
994	How to find this limit: $A=\lim_{n\to \infty}\sqrt{1+\sqrt{\frac{1}{2}+\sqrt{\frac{1}{3}+\cdots+\sqrt{\frac{1}{n}}}}}$
995	Visual proof of $\sum_{n=1}^\infty \frac{1}{n^4} = \frac{\pi^4}{90}$?
996	In $n>5$, topology = algebra
997	Conjectured formula for the Fabius function
998	Element-wise (or pointwise) operations notation?
999	Where exactly are complex numbers used in the real world?
1000	Is zero positive or negative?
1001	Prove that $\lim \limits_{n \to \infty} \frac{x^n}{n!} = 0$, $x \in \Bbb R$.
1002	Finding the Transform matrix from 4 projected points (with Javascript)
1003	Reference book on measure theory
1004	How to effectively and efficiently learn mathematics
1005	Logic problem: Identifying poisoned wines out of a sample, minimizing test subjects with constraints
1006	What is a universal property?
1007	Why are differentiable complex functions infinitely differentiable?
1008	Sheaf cohomology: what is it and where can I learn it?
1009	Koch snowflake paradox: finite area, but infinite perimeter
1010	I lost my love of math; Im getting it back. How can I determine if math is actually right for me?
1011	Is there a function with a removable discontinuity at every point?
1012	Direct proof that $\pi$ is not constructible
1013	Generalized Euler sum $\sum_{n=1}^\infty \frac{H_n}{n^q}$
1014	Rigorous nature of combinatorics
1015	Integrals of $\sqrt{x+\sqrt{\phantom|\dots+\sqrt{x+1}}}$ in elementary functions
1016	Escaping infinitely many pursuers
1017	Relations between p norms
1018	Projection map being a closed map
1019	Math behind rotation in MS Paint
1020	The Monty Hall problem
1021	Why is the Möbius strip not orientable?
1022	Help me solve my fathers riddle and get my book back
1023	Why did my friend lose all his money?
1024	What is lost when we move from reals to complex numbers?
1025	Is linear algebra more “fully understood” than other maths disciplines?
1026	Are these solutions of $2 = x^{x^{x^{\:\cdot^{\:\cdot^{\:\cdot}}}}}$ correct?
1027	How deep is the liquid in a half-full hemisphere?
1028	Why do books titled Abstract Algebra mostly deal with groups/rings/fields?
1029	What exactly are eigen-things?
1030	What is an example of a sequence which thins out and is finite?
1031	Why is $\omega$ the smallest $\infty$?
1032	Besides proving new theorems, how can a person contribute to mathematics?
1033	The Intuition behind lHopitals Rule
1034	Motivation for spectral graph theory.
1035	Mathematicians shocked(?) to find pattern in prime numbers
1036	Closed form for $\int_0^\infty\ln\frac{J_\mu(x)^2+Y_\mu(x)^2}{J_\nu(x)^2+Y_\nu(x)^2}\mathrm dx$
1037	Why cant the Polynomial Ring be a Field?
1038	A path to truly understanding probability and statistics
1039	Is there a shape with infinite area but finite perimeter?
1040	Infinite sets dont exist!?
1041	Fastest way to check if $x^y > y^x$?
1042	What is integration by parts, really?
1043	Conjectures (or intuitions) that turned out wrong in an interesting or useful way
1044	What is the intuition behind uniform continuity?
1045	Dividing 100% by 3 without any left
1046	Inscribing square in circle in just seven compass-and-straightedge steps
1047	List of interesting integrals for early calculus students
1048	The Duals of $l^\infty$ and $L^{\infty}$
1049	Finite subgroups of the multiplicative group of a field are cyclic
1050	Whats a proof that the angles of a triangle add up to 180°?
1051	Stirlings formula: proof?
1052	Is learning (theoretical) physics useful/important for a mathematician?
1053	An example of a problem which is difficult but is made easier when a diagram is drawn
1054	Multiple-choice: sum of primes below $1000$
1055	Fake induction proofs
1056	Theorem that von Neumann proved in five minutes.
1057	Why did mathematicians introduce the concept of uniform continuity?
1058	Why is $i! = 0.498015668 - 0.154949828i$?
1059	Gerrymandering on a high-genus surface/can I use my powers for evil?
1060	A strange integral: $\int_{-\infty}^{+\infty} {dx \over 1 + \left(x + \tan x\right)^2} = \pi.$
1061	Denesting radicals like $\sqrt[3]{\sqrt[3]{2} - 1}$
1062	How are mathematicians taught to write with such an expository style?
1063	Number of ways to write n as a sum of k nonnegative integers
1064	What is $\sqrt{i}$?
1065	Teenager solves Newton dynamics problem - where is the paper?
1066	Combinatorial proof of summation of $\sum\limits_{k = 0}^n {n \choose k}^2= {2n \choose n}$
1067	What is the meaning of the third derivative of a function at a point
1068	Continuous mapping on a compact metric space is uniformly continuous
1069	Prove that the set of all algebraic numbers is countable
1070	Difference between metric and norm made concrete: The case of Euclid
1071	(Theoretical) Multivariable Calculus Textbooks
1072	Quotient ring of Gaussian integers
1073	String Theory: What to do?
1074	What is the chance to get a parking ticket in half an hour if the chance to get a ticket is 80% in 1 hour?
1075	Why there is no sign of logic symbols in mathematical texts?
1076	Connections between metrics, norms and scalar products (for understanding e.g. Banach and Hilbert spaces)
1077	Interesting and unexpected applications of $\pi$
1078	How to prove this identity $\pi=\sum\limits_{k=-\infty}^{\infty}\left(\frac{\sin(k)}{k}\right)^{2}\;$?
1079	Thurstons 37th way of thinking about the derivative
1080	Volumes of n-balls: what is so special about n=5?
1081	Ramanujan log-trigonometric integrals
1082	Finding out the area of a triangle if the coordinates of the three vertices are given
1083	Factorial, but with addition
1084	A simple explanation of eigenvectors and eigenvalues with big picture ideas of why on earth they matter
1085	Zero probability and impossibility
1086	Whats the difference between stochastic and random?
1087	How many connected components does $\mathrm{GL}_n(\mathbb R)$ have?
1088	Mathematical subjects you wish you learned earlier
1089	Closed form for $\sum \frac{1}{n^n}$
1090	Why cant you pick socks using coin flips?
1091	Is it bad form to write mysterious proofs without explaining what one intends to do?
1092	Does $G\cong G/H$ imply that $H$ is trivial?
1093	What does the mysterious constant marked by C on a slide rule indicate?
1094	Two curious identities on $x^x$,$e$,and $\pi$
1095	How to find perpendicular vector to another vector?
1096	How to calculate $\,(a-b)\bmod n\,$ and $ {-}b \bmod n$
1097	How was the normal distribution derived?
1098	What is the proper way to study (more advanced) math?
1099	What are the applications of functional analysis?
1100	Very *mathematical* general physics book
1101	Why not include as a requirement that all functions must be continuous to be differentiable?
1102	Bag of tricks in Advanced Calculus/ Real Analysis/Complex Analysis
1103	What would have been our number system if humans had more than 10 fingers? Try to solve this puzzle.
1104	Does associativity imply commutativity?
1105	Algebraic Intuition for Homological Algebra and Applications to More Elementary Algebra
1106	A new imaginary number? $x^c = -x$
1107	About Euclids Elements and modern video games
1108	A matrix and its transpose have the same set of eigenvalues/other version: $A$ and $A^T$ have the same spectrum
1109	What is the math behind the game Spot It?
1110	Are the eigenvalues of $AB$ equal to the eigenvalues of $BA$? (Citation needed!)
1111	Why determinant of a 2 by 2 matrix is the area of a parallelogram?
1112	Intuition behind using complementary CDF to compute expectation for nonnegative random variables
1113	Proof that a Combination is an integer
1114	A map is continuous if and only if for every set, the image of closure is contained in the closure of image
1115	Examples of finite nonabelian groups.
1116	Whats going on with compact implies sequentially compact?
1117	Best Algebraic Geometry text book? (other than Hartshorne)
1118	Why does the symbol for the multiplication operation change shape?
1119	Hanging a picture on the wall using two nails in such a way that removing any nail makes the picture fall down
1120	Why does the google calculator give $\tan 90^{\circ} = 1.6331779e^{+16}$?
1121	Reference request: introduction to commutative algebra
1122	When writing in math, do you use a comma or colon preceding an equation?
1123	Is linear algebra laying the foundation for something important?
1124	How come $32.5 = 31.5$? (The Missing Square puzzle.)
1125	Evaluating $\int_0^\infty \sin x^2\, dx$ with real methods?
1126	Is there an easy way to show which spheres can be Lie groups?
1127	How to solve fifth-degree equations by elliptic functions?
1128	Intuition behind conjugation in group theory
1129	How to stop forgetting proofs - for a first course in Real Analysis?
1130	Polynomials irreducible over $\mathbb{Q}$ but reducible over $\mathbb{F}_p$ for every prime $p$
1131	How to find the inverse modulo $m$?
1132	Finding a point along a line a certain distance away from another point!
1133	Graph theory: adjacency vs incident
1134	Space of bounded continuous functions is complete
1135	Why is $\Gamma\left(\frac{1}{2}\right)=\sqrt{\pi}$?
1136	Simplest proof of Taylors theorem
1137	What algorithm is used by computers to calculate logarithms?
1138	Why do we need to learn integration techniques?
1139	Solving $DEF+FEF=GHH$, $KLM+KLM=NKL$, $ABC+ABC+ABC=BBB$
1140	Why can a real number be defined as a Dedekind cut, that is, as a set of rational numbers?
1141	Mathematical research of Pokémon
1142	Why Zariski topology?
1143	Why should we prove obvious things?
1144	Drunk man with a set of keys.
1145	Will assuming the existence of a solution ever lead to a contradiction?
1146	What is $x^y$? How to understand it?
1147	Lebesgue measure theory vs differential forms?
1148	Naturally occurring non-Hausdorff spaces?
1149	What are some mathematical topics that involve adding and multiplying pictures?
1150	How to cut a cube out of a tree stump, such that a pair of opposing vertices are in the center?
1151	Why are the last two numbers of this sequence never prime?
1152	Is $ 0.112123123412345123456\dots $ algebraic or transcendental?
1153	Integral $\int_1^\infty\frac{\operatorname{arccot}\left(1+\frac{2\pi}{\operatorname{arcoth}x-\operatorname{arccsc}x}\right)}{\sqrt{x^2-1}}\mathrm dx$
1154	Representing every positive rational number in the form of $(a^n+b^n)/(c^n+d^n)$
1155	Difference between Fourier transform and Wavelets
1156	Is there a known mathematical equation to find the nth prime?
1157	Understanding Borel sets
1158	$\infty = -1 $ paradox
1159	What do $\pi$ and $e$ stand for in the normal distribution formula?
1160	Completion of rational numbers via Cauchy sequences
1161	Convergence of $\sqrt{n}x_{n}$ where $x_{n+1} = \sin(x_{n})$
1162	Combinatorial proof that $\sum \limits_{k=0}^n \binom{2k}{k} \binom{2n-2k}{n-k} (-1)^k = 2^n \binom{n}{n/2}$ when $n$ is even
1163	Why does being holomorphic imply so much about a function?
1164	Why should I care about adjoint functors
1165	How did Euler prove the Mersenne number $2^{31}-1$ is a prime so early in history?
1166	Pseudo Proofs that are intuitively reasonable
1167	Is $\sqrt1+\sqrt2+\dots+\sqrt n$ ever an integer?
1168	Is this determinant identity known?
1169	How was the Monsters existence originally suspected?
1170	How to prove $\int_{-\infty}^{+\infty} f(x)dx = \int_{-\infty}^{+\infty} f\left(x - \frac{1}{x}\right)dx?$
1171	Conjecture $_2F_1\left(\frac14,\frac34;\,\frac23;\,\frac13\right)=\frac1{\sqrt{\sqrt{\frac4{\sqrt{2-\sqrt[3]4}}+\sqrt[3]{4}+4}-\sqrt{2-\sqrt[3]4}-2}}$
1172	What exactly is Laplace transform?
1173	$\sum k! = 1! +2! +3! + \cdots + n!$ ,is there a generic formula for this?
1174	Can a limit of an integral be moved inside the integral?
1175	If $G/Z(G)$ is cyclic, then $G$ is abelian
1176	Prove if $n^2$ is even, then $n$ is even.
1177	An Explanation of the Kalman Filter
1178	Geometric interpretation for complex eigenvectors of a 2×2 rotation matrix
1179	Proving that $1$- and $2D$ simple symmetric random walks return to the origin with probability $1$
1180	incremental computation of standard deviation
1181	Intuitive explanation of a definition of the Fisher information
1182	Not every metric is induced from a norm
1183	Why does multiplying a number on a clock face by 10 and then halving, give the minutes? ${}{}$
1184	Equivalent Definitions of the Operator Norm
1185	Is it morally right and pedagogically right to google answers to homework?
1186	Why is the complex plane shaped like it is?
1187	What are some applications of elementary linear algebra outside of math?
1188	How can one prove that $e<\pi$?
1189	Why does this miracle method for matrix inversion work?
1190	Is there an intuitive reason for a certain operation to be associative?
1191	Laplace, Legendre, Fourier, Hankel, Mellin, Hilbert, Borel, Z...: unified treatment of transforms?
1192	Are there infinitely many super-palindromes?
1193	Let, $A\subset\mathbb{R}^2$. Show that $A$ can contain at most one point $p$ such that $A$ is isometric to $A \setminus \{p\}$.
1194	Numerical phenomenon. Who can explain?
1195	Probability of 3 people in a room of 30 having the same birthday
1196	Difference between continuity and uniform continuity
1197	Compact sets are closed?
1198	What is mathematical research like?
1199	Difference between complete and closed set
1200	When does L Hopitals rule fail?
1201	In classical logic, why is $(p\Rightarrow q)$ True if $p$ is False and $q$ is True?
1202	Whats a good place to learn Lie groups?
1203	Why do we use a Least Squares fit?
1204	Chance of meeting in a bar
1205	What is the most expensive item I could buy with £50?
1206	Can someone please explain the Riemann Hypothesis to me... in English?
1207	Prove $0! = 1$ from first principles
1208	Why cant the second fundamental theorem of calculus be proved in just two lines?
1209	What is so interesting about the zeroes of the Riemann $\zeta$ function?
1210	Does every Abelian group admit a ring structure?
1211	Are there an infinite number of prime numbers where removing any number of digits leaves a prime?
1212	Japanese Temple Problem From 1844
1213	The limit of truncated sums of harmonic series, $\lim\limits_{k\to\infty}\sum_{n=k+1}^{2k}{\frac{1}{n}}$
1214	Understandable questions which are hard for non-mathematicians but easy for mathematicians
1215	Do there exist pairs of distinct real numbers whose arithmetic, geometric and harmonic means are all integers?
1216	Fractal behavior along the boundary of convergence?
1217	Are there any valid continuous Sudoku grids?
1218	A nasty integral of a rational function
1219	Show that $\int_{0}^{\pi/2}\frac {\log^2\sin x\log^2\cos x}{\cos x\sin x}\mathrm{d}x=\frac14\left( 2\zeta (5)-\zeta(2)\zeta (3)\right)$
1220	How much does symbolic integration mean to mathematics?
1221	Evaluating sums and integrals using Taylors Theorem
1222	How to show that $\det(AB) =\det(A) \det(B)$?
1223	What is the equation for a 3D line?
1224	Density of sum of two independent uniform random variables on $[0,1]$
1225	Use of without loss of generality
1226	Why is $\pi $ equal to $3.14159...$?
1227	$\sqrt{7\sqrt{7\sqrt{7\sqrt{7\sqrt{7\cdots}}}}}$ approximation
1228	Limit $\frac{x^2y}{x^4+y^2}$ is found using polar coordinates but it is not supposed to exist.
1229	What is the largest eigenvalue of the following matrix?
1230	Good books on Math History
1231	Why is a circle 1-dimensional?
1232	Overview of basic results on cardinal arithmetic
1233	Is The empty set is a subset of any set a convention?
1234	How do people apply the Lebesgue integration theory?
1235	Why is radian so common in maths?
1236	Why do engineers use derivatives in discontinuous functions? Is it correct?
1237	Why are addition and multiplication commutative, but not exponentiation?
1238	$100$-th derivative of the function $f(x)=e^{x}\cos(x)$
1239	Is it generally accepted that if you throw a dart at a number line you will NEVER hit a rational number?
1240	Is memory unimportant in doing mathematics?
1241	Theorems names that dont credit the right people
1242	What is the oldest open problem in geometry?
1243	Why the emphasis on Projective Space in Algebraic Geometry?
1244	Is there a great mathematical example for a 12-year-old?
1245	Am I too young to learn more advanced math and get a teacher?
1246	How to straighten a parabola?
1247	Geometric intuition for the tensor product of vector spaces
1248	How likely is it not to be anyones best friend?
1249	What is a real world application of polynomial factoring?
1250	What is the proof that the total number of subsets of a set is $2^n$?
1251	How to explain for my daughter that $\frac {2}{3}$ is greater than $\frac {3}{5}$?
1252	Where is the flaw in this proof that 1=2? (Derivative of repeated addition)
1253	How to write a good mathematical paper?
1254	What are the names of numbers in the binary system?
1255	Why $9$ & $11$ are special in divisibility tests using decimal digit sums? (casting out nines & elevens)
1256	Is it technically incorrect to write proofs forward?
1257	What Is Exponentiation?
1258	Why do I get one extra wrong solution when solving $2-x=-\sqrt{x}$?
1259	Mathematicians dont quit, they fade away
1260	If I know the order of every element in a group, do I know the group?
1261	Is it possible to find an infinite set of points in the plane where the distance between any pair is rational?
1262	Have there been efforts to introduce non Greek or Latin alphabets into mathematics?
1263	Algebra: Best mental images
1264	What is the average rational number?
1265	Is this similarity to the Fourier transform of the von Mangoldt function real?
1266	Closed form for $\int_0^1\log\log\left(\frac{1}{x}+\sqrt{\frac{1}{x^2}-1}\right)\mathrm dx$
1267	Topological spaces admitting an averaging function
1268	How do I tell if matrices are similar?
1269	What isnt a vector space?
1270	Prove that $\prod_{k=1}^{n-1}\sin\frac{k \pi}{n} = \frac{n}{2^{n-1}}$
1271	Why is Euclids proof on the infinitude of primes considered a proof?
1272	When not to treat dy/dx as a fraction in single-variable calculus?
1273	how to read a mathematical paper?
1274	Why do people lose in chess?
1275	Is it mathematically valid to separate variables in a differential equation?
1276	How much Math do you REALLY do in your job?
1277	What is the importance of the infinitesimal generator of Brownian motion?
1278	Do Parabolic Trigonometric Functions exist?
1279	Why is the tensor product important when we already have direct and semidirect products?
1280	Nuking the Mosquito — ridiculously complicated ways to achieve very simple results
1281	Are proofs by contradiction really logical?
1282	Is it possible to formulate category theory without set theory?
1283	What is the logic/rationale behind the vector cross product?
1284	Is there a simple function that generates the series; $1,1,2,1,1,2,1,1,2...$ or $-1,-1,1,-1,-1,1...$
1285	Integral $\int_0^1\frac{\ln\left(x+\sqrt2\right)}{\sqrt{2-x}\,\sqrt{1-x}\,\sqrt{\vphantom{1}x}}\mathrm dx$
1286	Can $18$ consecutive integers be separated into two groups,such that their product is equal?
1287	Integration of forms and integration on a measure space
1288	Simplicial homology of real projective space by Mayer-Vietoris
1289	Evaluating the log gamma integral $\int_{0}^{z} \log \Gamma (x) \, \mathrm dx$ in terms of the Hurwitz zeta function
1290	Does the string of prime numbers contain all natural numbers?
1291	Showing that $\int\limits_{-a}^a \frac{f(x)}{1+e^{x}} \mathrm dx = \int\limits_0^a f(x) \mathrm dx$, when $f$ is even
1292	Differential forms on fuzzy manifolds
1293	Difference between NFA and DFA
1294	Given this transformation matrix, how do I decompose it into translation, rotation and scale matrices?
1295	How can a probability density be greater than one and integrate to one
1296	Good books on mathematical logic?
1297	There are 4 cups of liquid. Three are water and one is poison. If you were to drink 3 of the 4 cups, what is the probability of being poisoned?
1298	How to convince a layperson that the $\pi = 4$ proof is wrong?
1299	Every subsequence of $x_n$ has a further subsequence which converges to $x$. Then the sequence $x_n$ converges to $x$.
1300	Intuitive explanation of a positive semidefinite matrix
1301	Proving that the tensor product is right exact
1302	Integrals of the form ${\large\int}_0^\infty\operatorname{arccot}(x)\cdot\operatorname{arccot}(a\,x)\cdot\operatorname{arccot}(b\,x)\ dx$
1303	Express 99 2/3% as a fraction? No calculator
1304	What exactly is calculus?
1305	Does it ever make sense NOT to go to the most prestigious graduate school you can get into?
1306	Set of continuity points of a real function
1307	Does every prime divide some Fibonacci number?
1308	Does $\sum _{n=1}^{\infty } \frac{\sin(\text{ln}(n))}{n}$ converge?
1309	Understanding the Laplace operator conceptually
1310	What is Cauchy Schwarz in 8th grade terms?
1311	Proving the existence of a proof without actually giving a proof
1312	How and why does Grothendiecks work provide tools to attack problems in number theory?
1313	Limits: How to evaluate $\lim\limits_{x\rightarrow \infty}\sqrt[n]{x^{n}+a_{n-1}x^{n-1}+\cdots+a_{0}}-x$
1314	Does multiplying all a numbers roots together give a product of infinity?
1315	What are some good ways to get children excited about math?
1316	Why does $\cos(x) + \cos(y) - \cos(x + y) = 0$ look like an ellipse?
1317	When is an infinite product of natural numbers regularizable?
1318	Why is it not true that $\int_0^{\pi} \sin(x)\; dx = 0$?
1319	Evaluating $\int_{0}^{1}\cdots\int_{0}^{1}\bigl\{\frac{1}{x_{1}\cdots x_{n}}\bigr\}^{2}\:\mathrm{d}x_{1}\cdots\mathrm{d}x_{n}$
1320	Are the sums $\sum_{n=1}^{\infty} \frac{1}{(n!)^k}$ transcendental?
1321	Does $\Bbb{CP}^{2n} \mathbin{\#} \Bbb{CP}^{2n}$ ever support an almost complex structure?
1322	Closed form solution for $\sum_{n=1}^\infty\frac{1}{1+\frac{n^2}{1+\frac{1}{\stackrel{\ddots}{1+\frac{1}{1+n^2}}}}}$.
1323	What is a good book for learning math, from middle school level?
1324	difference between dot product and inner product
1325	Check if a point is within an ellipse
1326	What does proving the Riemann Hypothesis accomplish?
1327	Is Serge Langs Algebra still worth reading?
1328	Highest power of a prime $p$ dividing $N!$
1329	Proof that Pi is constant (the same for all circles), without using limits
1330	Interesting real life applications of serious theorems
1331	How do I motivate myself to do math again?
1332	Under what conditions the quotient space of a manifold is a manifold?
1333	How to effectively study math?
1334	Is there any branch of Mathematics which has no applications in any other field or in real world?
1335	Nice expression for minimum of three variables?
1336	What exactly is a number?
1337	Dominoes and induction, or how does induction work?
1338	Riemann hypothesis: is Bender-Brody-Müller Hamiltonian a new line of attack?
1339	Why do we not have to prove definitions?
1340	Optimal strategy for cutting a sausage?
1341	Symbol for probably equal to (barring pathology)?
1342	Is it not effective to learn math top-down?
1343	If we randomly select 25 integers between 1 and 100, how many consecutive integers should we expect?
1344	A new general formula for the quadratic equation?
1345	Conways Murder Weapon
1346	How to explain to the layperson what mathematics is, why its important, and why its interesting
1347	Is the box topology good for anything?
1348	Does the series $ \sum\limits_{n=1}^{\infty} \frac{1}{n^{1 + |\sin(n)|}} $ converge or diverge?
1349	Does Fermats Last Theorem hold for cyclotomic integers in $\mathbb{Q(\zeta_{37})}$?
1350	In combinatorics, how can one verify that one has counted correctly?
1351	Algebraic Topology Challenge: Homology of an Infinite Wedge of Spheres
1352	Fourier Transform of Derivative
1353	What is the relation between rank of a matrix, its eigenvalues and eigenvectors
1354	What is the standard basis for fields of complex numbers?
1355	Good books for a high schooler self-studying Abstract Algebra?
1356	Why do the French count so strangely?
1357	A comprehensive list of binomial identities?
1358	What is a covector and what is it used for?
1359	First-Order Logic vs. Second-Order Logic
1360	Why is the determinant the volume of a parallelepiped in any dimensions?
1361	Introductory texts on manifolds
1362	Functions that are their own inverse.
1363	How do I convince my students that the choice of variable of integration is irrelevant?
1364	If a coin toss is observed to come up as heads many times, does that affect the probability of the next toss?
1365	A way to find this shaded area without calculus?
1366	Learning Roadmap for Algebraic Topology
1367	What is the limit of $n \sin (2 \pi \cdot e \cdot n!)$ as $n$ goes to infinity?
1368	How does a non-mathematician go about publishing a proof in a way that ensures it to be up to the mathematical communitys standards?
1369	When to give up on a hard math problem?
1370	Simplicial Complex vs Delta Complex vs CW Complex
1371	Why are primes considered to be the building blocks of the integers?
1372	What are some mathematically interesting computations involving matrices?
1373	Arranging numbers from $1$ to $n$ such that the sum of every two adjacent numbers is a perfect power
1374	Given real numbers: define integers?
1375	Arc length contest! Minimize the arc length of $f(x)$ when given three conditions.
1376	Is $ \sum\limits_{n=1}^\infty \frac{|\sin n|^n}n$ convergent？
1377	What does strength refer to in mathematics?
1378	Is there a reason it is so rare we can solve differential equations?
1379	Why it is important to write a function as sum of even and odd functions?
1380	What is a proof?
1381	Area covered by a constant length segment rotating around the center of a square.
1382	Is it normal to treat Math Theorems as Black Boxes
1383	Good history of mathematical ideas book?
1384	Abstract nonsense proof of snake lemma
1385	How to find a total order with constrained comparisons
1386	Integers $n$ such that $i(i+1)(i+2) \cdots (i+n)$ is real or pure imaginary
1387	Which Algebraic Properties Distinguish Lie Groups from Abstract Groups?
1388	I have learned that 1/0 is infinity, why isnt it minus infinity?
1389	Difference between axioms, theorems, postulates, corollaries, and hypotheses
1390	Is the sum and difference of two irrationals always irrational?
1391	What is the difference between the Frobenius norm and the 2-norm of a matrix?
1392	How does a calculator calculate the sine, cosine, tangent using just a number?
1393	How do you compute negative numbers to fractional powers?
1394	Proving $1^3+ 2^3 + \cdots + n^3 = \left(\frac{n(n+1)}{2}\right)^2$ using induction
1395	Probability that random moves in the game 2048 will win
1396	Why does $\tan^{-1}(1)+\tan^{-1}(2)+\tan^{-1}(3)=\pi$?
1397	Proof of the Hockey-Stick Identity: $\sum\limits_{t=0}^n \binom tk = \binom{n+1}{k+1}$
1398	How can you prove that the square root of two is irrational?
1399	Is the Law of Large Numbers empirically proven?
1400	Cardinality of Borel sigma algebra
1401	Motivation and methods for self-study
1402	Intuition on group homomorphisms
1403	Can someone explain the Yoneda Lemma to an applied mathematician?
1404	Polynomial division: an obvious trick? [reducing mod $\textit{simpler}$ multiples]
1405	How can I introduce complex numbers to precalculus students?
1406	$n$th derivative of $e^{1/x}$
1407	What should an amateur do with a proof of an open problem?
1408	Why does an exponential function eventually get bigger than a quadratic
1409	Big List of Erdős elementary proofs
1410	Continuity and the Axiom of Choice
1411	Graphs for which a calculus student can reasonably compute the arclength
1412	Conjugate subgroup strictly contained in the initial subgroup?
1413	Rigour in mathematics
1414	Where does the word torsion in algebra come from?
1415	Computation with a memory wiped computer
1416	Let $k$ be a natural number . Then $3k+1$ , $4k+1$ and $6k+1$ cannot all be square numbers.
1417	Unexpected approximations which have led to important mathematical discoveries
1418	On Ramanujans curious equality for $\sqrt{2\,(1-3^{-2})(1-7^{-2})(1-11^{-2})\cdots} $
1419	Is $\lfloor n!/e\rfloor$ always even for $n\in\mathbb N$?
1420	How do I prove that a function is well defined?
1421	Is the rank of a matrix the same of its transpose? If yes, how can I prove it?
1422	Evaluating the indefinite integral $ \int \sqrt{\tan x} ~ \mathrm{d}{x}. $
1423	Proof that the irrational numbers are uncountable
1424	Can a complex number ever be considered bigger or smaller than a real number, or vice versa?
1425	Prove every odd integer is the difference of two squares
1426	how to be good at proving?
1427	Are there any examples of non-computable real numbers?
1428	What is a good book to study linear algebra?
1429	Why is empty set an open set?
1430	How to prove and interpret $\operatorname{rank}(AB) \leq \operatorname{min}(\operatorname{rank}(A), \operatorname{rank}(B))$?
1431	Probability for the length of the longest run in $n$ Bernoulli trials
1432	Proof of $(\mathbb{Z}/m\mathbb{Z}) \otimes_\mathbb{Z} (\mathbb{Z} / n \mathbb{Z}) \cong \mathbb{Z}/ \gcd(m,n)\mathbb{Z}$
1433	What do prime ideals in $k[x,y]$ look like?
1434	Characterizing units in polynomial rings
1435	Entire one-to-one functions are linear
1436	Let $X$ be an infinite dimensional Banach space. Prove that every Hamel basis of X is uncountable.
1437	How do you show monotonicity of the $\ell^p$ norms?
1438	Strategies to denest nested radicals $\sqrt{a+b\sqrt{c}}$
1439	How would you explain to a 9th grader the negative exponent rule?
1440	Why learn to solve differential equations when computers can do it?
1441	Big List of Fun Math Books
1442	What is the definition of a set?
1443	Is there such a thing as proof by example (not counter example)
1444	Can there be two distinct, continuous functions that are equal at all rationals?
1445	Whats the goal of mathematics?
1446	How to debug math?
1447	What does communicated by mean in math papers?
1448	Using Gröbner bases for solving polynomial equations
1449	Which is larger? $20!$ or $2^{40}$?
1450	Unsolved Problems due to Lack of Computational Power
1451	Whats wrong with this reasoning that $\frac{\infty}{\infty}=0$?
1452	Are there theoretical applications of trigonometry?
1453	The last digit of $2^{2006}$
1454	Intuition for the Importance of Modular Forms
1455	Linear Algebra Versus Functional Analysis
1456	Whats the point of studying topological (as opposed to smooth, PL, or PDiff) manifolds?
1457	Find three non-constant, pairwise unequal functions $f,g,h:\mathbb R\to \mathbb R$...
1458	Surprisingly elementary and direct proofs
1459	Closed Form for $~\int_0^1\frac{\text{arctanh }x}{\tan\left(\frac\pi2~x\right)}~dx$
1460	Is $n \sin n$ dense on the real line?
1461	When are nonintersecting finite degree field extensions linearly disjoint?
1462	The relation between trace and determinant of a matrix
1463	How to prove every closed interval in R is compact?
1464	Is there a step by step checklist to check if a multivariable limit exists and find its value?
1465	Is an automorphism of the field of real numbers the identity map?
1466	What do eigenvalues have to do with pictures?
1467	Why cant you flatten a sphere?
1468	List of problem books in undergraduate and graduate mathematics
1469	What is the importance of Calculus in todays Mathematics?
1470	Why does $\frac{1}{x} < 4$ have two answers?
1471	Explain this mathematical meme (Geometers bird interrupting Topologists bird)
1472	Coin flipping probability game ; 7 flips vs 8 flips
1473	Finite Groups with exactly $n$ conjugacy classes $(n=2,3,...)$
1474	Help understanding Algebraic Geometry
1475	7 fishermen caught exactly 100 fish and no two had caught the same number of fish. Then there are three who have together captured at least 50 fish.
1476	Can a number have infinitely many digits before the decimal point?
1477	How can I show that $\sqrt{1+\sqrt{2+\sqrt{3+\sqrt\ldots}}}$ exists?
1478	Whats the intuition with partitions of unity?
1479	Center-commutator duality
1480	In how many different ways can a 9-panel comic grid be used?
1481	I need mathematical proof that the distance from zero to 1 is the equal to the distance from 1 to 2
1482	I almost quit self-studying mathematics, but should I continue?
1483	What is Trinity Hall Prime number?
1484	Examples of morphisms of schemes to keep in mind?
1485	Review of my T-shirt design
1486	Determinant of a rank $1$ update of a scalar matrix, or characteristic polynomial of a rank $1$ matrix
1487	Is A New Kind of Science a new kind of science?
1488	What am I doing when I separate the variables of a differential equation?
1489	Does every set have a group structure?
1490	Why do we use trig functions in Fourier transforms, and not other periodic functions?
1491	How to evaluate $I=\int_0^{\pi/2}x^2\ln(\sin x)\ln(\cos x)\ \mathrm dx$
1492	Is it possible to simplify $\frac{\Gamma\left(\frac{1}{10}\right)}{\Gamma\left(\frac{2}{15}\right)\ \Gamma\left(\frac{7}{15}\right)}$?
1493	Can squares of infinite area always cover a unit square?
1494	Whats the probability that a sequence of coin flips never has twice as many heads as tails?
1495	$5^n+n$ is never prime?
1496	What does it take to divide by $2$?
1497	If a two variable smooth function has two global minima, will it necessarily have a third critical point?
1498	Subgroups as isotropy subgroups and regular orbits on tuples
1499	A question about Sylow subgroups and $C_G(x)$
1500	How to know if a point is inside a circle?
1501	Poisson Distribution of sum of two random independent variables $X$, $Y$
1502	Explanation on arg min
1503	Product of two Gaussian PDFs is a Gaussian PDF, but Product of two Gaussian Variables is not Gaussian
1504	Is the product of symmetric positive semidefinite matrices positive definite?
1505	Matrices commute if and only if they share a common basis of eigenvectors?
1506	What are the formal names of operands and results for basic operations?
1507	Differentiating an Inner Product
1508	How to show that the commutator subgroup is a normal subgroup
1509	Nobody told me that self teaching could be so damaging...
1510	(undergraduate) Algebraic Geometry Textbook Recommendations
1511	Why is $\mathbb{Z}[\sqrt{-n}], n\ge 3$ not a UFD?
1512	Dot Product Intuition
1513	Divisor -- line bundle correspondence in algebraic geometry
1514	How to tell if Im good enough for graduate school?
1515	How is the derivative truly, literally the best linear approximation near a point?
1516	Why is the Continuum Hypothesis (not) true?
1517	Good examples of double induction
1518	A very general method for proving inequalities. Too good to be true?
1519	Is it possible to have three real numbers that have both their sum and product equal to $1$?
1520	What was the book that opened your mind to the beauty of mathematics?
1521	Research done by high-school students
1522	Why does the discriminant in the Quadratic Formula reveal the number of real solutions?
1523	Understanding the intuition behind math
1524	A circle rolls along a parabola
1525	Why is $\varphi$ called the most irrational number?
1526	How can I intuitively understand complex exponents?
1527	It looks straightforward, but actually it isnt
1528	Refuting the Anti-Cantor Cranks
1529	Could I be using proof by contradiction too much?
1530	Is there any geometric intuition for the factorials in Taylor expansions?
1531	Why do differential forms have a much richer structure than vector fields?
1532	A Challenging Logarithmic Integral $\int_0^1 \frac{\log(x)\log(1-x)\log^2(1+x)}{x}dx$
1533	Quadratic reciprocity via generalized Fibonacci numbers?
1534	Penroses remark on impossible figures
1535	Why are asymptotically one half of the integer compositions gap-free?
1536	Mirror algorithm for computing $\pi$ and $e$ - does it hint on some connection between them?
1537	Difference between ≈, ≃, and ≅
1538	What is the difference between only if and iff?
1539	Gradient of squared $2$-norm
1540	Distance/Similarity between two matrices
1541	Are all eigenvectors, of any matrix, always orthogonal?
1542	Area of a square inside a square created by connecting point-opposite midpoint
1543	How to generate random points on a sphere?
1544	Number of monic irreducible polynomials of prime degree $p$ over finite fields
1545	Should I be worried that I am doing well in analysis and not well in algebra?
1546	Negative versus Minus
1547	Discontinuous linear functional
1548	Geometric interpretation for sum of fourth powers
1549	The two-daughter-problem
1550	Has there ever been an application of dividing by $0$?
1551	Why do we miss 8 in the decimal expansion of 1/81, and 98 in the decimal expansion of 1/9801?
1552	Why does the Cauchy-Schwarz Inequality even have a name?
1553	What use is the Yoneda lemma?
1554	Is there a function whose antiderivative can be found but whose derivative cannot?
1555	Similar matrices and field extensions
1556	Are there mathematical concepts that exist in dimension $4$, but not in dimension $3$?
1557	Is there a definition of determinants that does not rely on how they are calculated?
1558	Unexpected use of topology in proofs
1559	Does this Fractal Have a Name?
1560	How is the Gödels Completeness Theorem not a tautology?
1561	How many 7-note musical scales are possible within the 12-note system?
1562	Approximating a $\sigma$-algebra by a generating algebra
1563	How do different definitions of degree coincide?
1564	What is the size of each side of the square?
1565	A non-losing strategy for tic-tac-toe $\times$ tic-tac-toe
1566	Can there be an injective function whose derivative is equivalent to its inverse function?
1567	Evaluating $\int_0^\infty \frac{dx}{\sqrt{x}[x^2+(1+2\sqrt{2})x+1][1-x+x^2-x^3+...+x^{50}]}$
1568	Trigonometric sums related to the Verlinde formula
1569	A bestiary about adjunctions
1570	Is OEIS A248049 an integer sequence?
1571	Prove that $\int_{0}^{1}\sin{(\pi x)}x^x(1-x)^{1-x}\,dx =\frac{\pi e}{24} $
1572	Golden Number Theory
1573	Explicit norm on $\mathcal{C}^0(\mathbb{R},\mathbb{R})$
1574	An illusionist and their assistant are about to perform the following magic trick
1575	The most effective windshield-wiper setup. (Packing a square with sectors)
1576	How prove this inequality $\sin{\sin{\sin{\sin{x}}}}\le\frac{4}{5}\cos{\cos{\cos{\cos{x}}}}$
1577	Period of the sum/product of two functions
1578	Example of Partial Order thats not a Total Order and why?
1579	What does curly (curved) less than sign $\succcurlyeq$ mean?
1580	Why we consider log likelihood instead of Likelihood in Gaussian Distribution
1581	Is there an equation to describe regular polygons?
1582	Eigenvalues of the rank one matrix $uv^T$
1583	Under what condition we can interchange order of a limit and a summation?
1584	Calculating pi manually
1585	Difference between basis and subbasis in a topology?
1586	Visualizing the 4th dimension.
1587	Why does the derivative of sine only work for radians?
1588	Origin of the dot and cross product?
1589	What is the arithmetic mean of no numbers?
1590	The $\sigma$-algebra of subsets of $X$ generated by a set $\mathcal{A}$ is the smallest sigma algebra including $\mathcal{A}$
1591	Would a proof to the Riemann Hypothesis affect security?
1592	What lies beyond the Sedenions
1593	Is it possible to determine if you were on a Möbius strip?
1594	Big O Notation is element of or is equal
1595	Is there a slowest rate of divergence of a series?
1596	Any smart ideas on finding the area of this shaded region?
1597	Can we calculate $ i\sqrt { i\sqrt { i\sqrt { \cdots } } }$?
1598	Is it possible that A counter-example exists but it cannot be found
1599	Applications of complex numbers to solve non-complex problems
1600	Is it an abuse of language to say *the* integers, *the* rational numbers, or *the* real numbers, etc.?
1601	Paradox: increasing sequence that goes to $0$?
1602	Is it possible to prove a mathematical statement by proving that a proof exists?
1603	Is $6.12345678910111213141516171819202122\ldots$ transcendental?
1604	Big list of guided discovery books
1605	Are there any Turing-undecidable problems whose undecidability is independent of the Halting problem?
1606	Funny double infinite sum
1607	Geometry problem involving infinite number of circles
1608	What proportion of positive integers have two factors that differ by 1?
1609	What are Different Approaches to Introduce the Elementary Functions?
1610	Finding triplets $(a,b,c)$ such that $\sqrt{abc}\in\mathbb N$ divides $(a-1)(b-1)(c-1)$
1611	How to think of the group ring as a Hopf algebra?
1612	Whats the value of this Viète-style product involving the golden ratio?
1613	Is $1+x+\frac{x^2}2+\dots+\frac{x^n}{n!}$ irreducible?
1614	How many values of $2^{2^{2^{.^{.^{.^{2}}}}}}$ depending on parenthesis?
1615	Looking for a definitive source about Dirichlet finally proving the Unit Theorem in the Sistine Chapel
1616	Whats the sign of $\det\left(\sqrt{i^2+j^2}\right)_{1\le i,j\le n}$?
1617	Is there a good reason why $\left\lfloor \frac{n!}{11e}\right\rfloor$ is always even?
1618	What does E mean in 9.0122222900391E-5?
1619	What’s the difference between analytical and numerical approaches to problems?
1620	How to find the multiplicity of eigenvalues?
1621	Is the power set of the natural numbers countable?
1622	Finding $\int x^xdx$
1623	Calculate on which side of a straight line is a given point located?
1624	Generating correlated random numbers: Why does Cholesky decomposition work?
1625	product distribution of two uniform distribution, what about 3 or more
1626	Dantzigs unsolved homework problems
1627	Interesting math-facts that are visually attractive
1628	How does TREE(3) grow to get so big? (Laymen explanation)
1629	Order of general- and special linear groups over finite fields.
1630	Why are two permutations conjugate iff they have the same cycle structure?
1631	What is an operator in mathematics?
1632	Does $ \int_0^{\infty}\frac{\sin x}{x}dx $ have an improper Riemann integral or a Lebesgue integral?
1633	Are there any differences between tensors and multidimensional arrays?
1634	Is it possible to write a sum as an integral to solve it?
1635	Why divide by $2m$
1636	Can math be subjective?
1637	Is there an easy way to see associativity or non-associativity from an operations table?
1638	Matrix is conjugate to its own transpose
1639	Is there a third dimension of numbers?
1640	Proving that $m+n\sqrt{2}$ is dense in $\mathbb R$
1641	What is the antiderivative of $e^{-x^2}$
1642	Is there a math expression equivalent to the conditional ternary operator?
1643	Understanding Gödels Incompleteness Theorem
1644	Do harmonic numbers have a “closed-form” expression?
1645	Is $\{0\}$ a field?
1646	How hard is the proof of $\pi$ or $e$ being transcendental?
1647	Interesting results easily achieved using complex numbers
1648	All natural numbers are equal.
1649	Geometrical interpretation of Ricci curvature
1650	Why are real numbers useful?
1651	$x^p-c$ has no root in a field $F$ if and only if $x^p-c$ is irreducible?
1652	What kind of work do modern day algebraists do?
1653	Choice of $q$ in Baby Rudins Example 1.1
1654	Why is there never a proof that extending the reals to the complex numbers will not cause contradictions?
1655	Is there any conjecture that we know is provable/disprovable but we havent found a proof of yet?
1656	Gaps or holes in rational number system
1657	What is $-i$ exactly?
1658	What knot is this?
1659	Doesnt the unprovability of the continuum hypothesis prove the continuum hypothesis?
1660	What is the fastest/most efficient algorithm for estimating Eulers Constant $\gamma$?
1661	What is the crime of lèse-Bourbaki?
1662	Natural example of cosets
1663	Is Complex Analysis equivalent Real Analysis with $f:\mathbb R^2 \to \mathbb R^2$?
1664	If $e^A$ and $e^B$ commute, do $A$ and $B$ commute?
1665	A discrete math riddle
1666	How does one give a mathematical talk?
1667	Probability that a quadratic equation has real roots
1668	How to identify surfaces of revolution
1669	Is there an abstract definition of a matrix being upper triangular?
1670	Self-learning mathematics - help needed!
1671	What is this pattern called?
1672	The $100$th derivative of $(x^2 + 1)/(x^3 - x)$
1673	Evaluate $\int_0^1\left(\frac{1}{\ln x} + \frac{1}{1-x}\right)^2 \mathrm dx$
1674	Infinite Series $\sum\limits_{n=1}^\infty\frac{(H_n)^2}{n^3}$
1675	In which ordered fields does absolute convergence imply convergence?
1676	Crazy pattern in the simple continued fraction for $\sum_{k=1}^\infty \frac{1}{(2^k)!}$
1677	A sequence that avoids both arithmetic and geometric progressions
1678	Proof of triangle inequality
1679	How to find the factorial of a fraction?
1680	What is the general equation of the ellipse that is not in the origin and rotated by an angle?
1681	Prove that the union of countably many countable sets is countable.
1682	Symbol for elementwise multiplication of vectors
1683	Difference between supremum and maximum
1684	What is difference between a ring and a field?
1685	Picking random points in the volume of sphere with uniform probability
1686	Necessity/Advantage of LU Decomposition over Gaussian Elimination
1687	Introductory Group theory textbook
1688	Does non-symmetric positive definite matrix have positive eigenvalues?
1689	Difference between Analytic and Holomorphic function
1690	Evaluating the nested radical $ \sqrt{1 + 2 \sqrt{1 + 3 \sqrt{1 + \cdots}}} $.
1691	Do matrices $ AB $ and $ BA $ have the same minimal and characteristic polynomials?
1692	What does it take to get a job at a top 50 math program in the U.S.?
1693	Is an irrational number odd or even?
1694	Definitions of Hessian in Riemannian Geometry
1695	How to calculate the pullback of a $k$-form explicitly
1696	How to prove that $\log(x)1$?
1697	Exam with $12$ yes/no questions (half yes, half no) and $8$ correct needed to pass, is it better to answer randomly or answer exactly 6 times yes?
1698	Distinguishing probability measure, function and distribution
1699	False proof: $\pi = 4$, but why?
1700	Books about the Riemann Hypothesis
1701	Why is $\text{Hom}(V,W)$ the same thing as $V^* \otimes W$?
1702	What is exactly the difference between a definition and an axiom?
1703	Non-associative operations
1704	Is $\sqrt{64}$ considered $8$? or is it $8,-8$?
1705	What is $\int_0^1\frac{x^7-1}{\log(x)}\mathrm dx$?
1706	Mathematical explanation behind a picture posted (lifted from facebook)
1707	Path-connected and locally connected space that is not locally path-connected
1708	Can I search for factors of $\ (11!)!+11!+1\ $ efficiently?
1709	Solutions to the matrix equation $\mathbf{AB-BA=I}$ over general fields
1710	Square root confusion: Why am I getting an answer if it doesnt work?
1711	Geometric understanding of differential forms.
1712	Why are the only division algebras over the real numbers the real numbers, the complex numbers, and the quaternions?
1713	What is the formula for pi used in the Python decimal library?
1714	Intuition for why the difference between $\frac{2x^2-x}{x^2-x+1}$ and $\frac{x-2}{x^2-x+1}$ is a constant?
1715	Axiom of choice and automorphisms of vector spaces
1716	Show that floating point $\sqrt{x \cdot x} \geq x$ for all long $x$.
1717	How to entertain a crowd with mathematics?
1718	Colliding Bullets
1719	False beliefs about Lebesgue measure on $\mathbb{R}$
1720	Evaluating $\int P(\sin x, \cos x) \text{d}x$
1721	Is there a geometric idea behind Sylows theorems?
1722	Is $29$ the only prime of the form $p^p+2$?
1723	Is Stokes Theorem natural in the sense of category theory?
1724	Trying to define $\mathbb{R}^{0.5}$ topologically
1725	Conjectured value of a harmonic sum $\sum_{n=1}^\infty\left(H_n-\,2H_{2n}+H_{4n}\right)^2$
1726	Elementary proof that the derivative of a real function is continuous somewhere
1727	Can $\sqrt{p}^{\sqrt{p}^{\sqrt{p}}}$ be an integer, if $p$ is a non-square positive integer?
1728	How to tell if a set of vectors spans a space?
1729	Easy way of memorizing values of sine, cosine, and tangent
1730	What does ∈ mean?
1731	Recognizable vs Decidable
1732	Why have we chosen our number system to be decimal (base 10)?
1733	How the product of two integrals is iterated integral? $\int\cdot \int = \iint$
1734	How to take the gradient of the quadratic form?
1735	Why cant a set have two elements of the same value?
1736	Order of finite fields is $p^n$
1737	Why is $A^TA$ invertible if $A$ has independent columns?
1738	Proof that the largest eigenvalue of a stochastic matrix is $1$
1739	how does expectation maximization work?
1740	Are functions of independent variables also independent?
1741	What is an intuitive explanation for $\operatorname{div} \operatorname{curl} F = 0$?
1742	What is the difference between projected gradient descent and ordinary gradient descent?
1743	Functions which are Continuous, but not Bicontinuous
1744	Choose a random number between $0$ and $1$ and record its value. Keep doing it until the sum of the numbers exceeds $1$. How many tries do we need?
1745	How I can prove that the sequence $\sqrt{2} , \sqrt{2\sqrt{2}}, \sqrt{2\sqrt{2\sqrt{2}}}$ converges to 2?
1746	Difference between bijection and isomorphism?
1747	$\lim\limits_{n \to{+}\infty}{\sqrt[n]{n!}}$ is infinite
1748	An easy example of a non-constructive proof without an obvious fix?
1749	Why doesnt induction extend to infinity? (re: Fourier series)
1750	A really complicated calculus book
1751	Why isnt several complex variables as fundamental as multivariable calculus?
1752	Parabola is an ellipse, but with one focal point at infinity
1753	Formal definition of conditional probability
1754	Why is it worth spending time on type theory?
1755	Why is cross product defined in the way that it is?
1756	What are the rules for equals signs with big-O and little-o?
1757	What book can bridge high school math and the more advanced topics?
1758	Foundation for analysis without axiom of choice?
1759	Intuition behind ideal
1760	How far is the list of known primes known to be complete?
1761	Why the real and imaginary parts of a complex analytic function are not independent?
1762	Do circles divide the plane into more regions than lines?
1763	On the functional square root of $x^2+1$
1764	$n!+1$ being a perfect square
1765	Does $\zeta(3)$ have a connection with $\pi$?
1766	Why do we need so many trigonometric definitions?
1767	Prove that the sum of pythagorean triples is always even
1768	What is the explanation for this visual proof of the sum of squares?
1769	Why are topological spaces interesting to study?
1770	Good math books to discover stuff by yourself
1771	Integral $\int_{-1}^{1} \frac{1}{x}\sqrt{\frac{1+x}{1-x}} \log \left( \frac{(r-1)x^{2} + sx + 1}{(r-1)x^{2} - sx + 1} \right) \, \mathrm dx$
1772	Why is it that $\mathbb{Q}$ cannot be homeomorphic to _any_ complete metric space?
1773	Why is the Laplacian important in Riemannian geometry?
1774	MIT 2015 Integration Question
1775	Is there a name for this type of polygon?
1776	Intuition behind Snake Lemma
1777	Is it possible for a function to be smooth everywhere, analytic nowhere, yet Taylor series at any point converges in a nonzero radius?
1778	Proof that a trigonometric function of a rational angle must be non-transcendental
1779	Does $|n^2 \cos n|$ diverge to $+\infty$?
1780	What are exact sequences, metaphysically speaking?
1781	What structure does the alternating group preserve?
1782	About the integral $\int_{0}^{+\infty}\sin(x\,\log x)\,dx$
1783	Effective Research Notes
1784	A new continued fraction for Apérys constant, $\zeta(3)$?
1785	Two questions about weakly convergent series related to $\sin(n^2)$ and Weyls inequality
1786	What is the integral of 1/x?
1787	How does one denote the set of all positive real numbers?
1788	Prove: If a sequence converges, then every subsequence converges to the same limit.
1789	How many prime numbers are known?
1790	What books are prerequisites for Spivaks Calculus?
1791	Create unique number from 2 numbers
1792	What is the main difference between a vector space and a field?
1793	If eigenvalues are positive, is the matrix positive definite?
1794	$\epsilon$-$\delta$ proof that $\lim\limits_{x \to 1} \frac{1}{x} = 1$.
1795	Finding Value of the Infinite Product $\prod \Bigl(1-\frac{1}{n^{2}}\Bigr)$
1796	Pen, pencils and paper to write math
1797	Video lectures on Real Analysis?
1798	If $a^3 =a$ for all $a$ in a ring $R$, then $R$ is commutative.
1799	Which of the numbers $1, 2^{1/2}, 3^{1/3}, 4^{1/4}, 5^{1/5}, 6^{1/6} , 7^{1/7}$ is largest, and how to find out without calculator?
1800	Zero divided by zero must be equal to zero
1801	Proof that every number ≥ $8$ can be represented by a sum of fives and threes.
1802	What is the difference between a Ring and an Algebra?
1803	Intuitive understanding of the derivatives of $\sin x$ and $\cos x$
1804	A linear operator commuting with all such operators is a scalar multiple of the identity.
1805	Prove that if $(ab)^i = a^ib^i \forall a,b\in G$ for three consecutive integers $i$ then G is abelian
1806	Is $\pi$ equal to $180^\circ$?
1807	Is every Lebesgue measurable function on $\mathbb{R}$ the pointwise limit of continuous functions?
1808	Seeking a laymans guide to Measure Theory
1809	What are the Laws of Rational Exponents?
1810	An intuitive approach to the Jordan Normal form
1811	Intuitive Understanding of the constant $e$
1812	How far can one see over the ocean?
1813	Every power series is the Taylor series of some $C^{\infty}$ function
1814	Is the axiom of choice really all that important?
1815	On average, how many friends would I need to have to have at least one friends birthday every day?
1816	Is there a purely algebraic proof of the Fundamental Theorem of Algebra?
1817	What books should I get to self study beyond Calculus for someone about to start undergrad mathematics?
1818	Are there any objects which arent sets?
1819	What is the theme of analysis?
1820	Is there any geometric way to characterize $e$?
1821	Why and How do certain manipulations in indefinite integrations just work?
1822	History of the Concept of a Ring
1823	Simplest way to get the lower bound $\pi > 3.14$
1824	What to answer when people ask what I do in mathematics
1825	How many super imaginary numbers are there?
1826	Fibonacci infinite sum resulting in $\pi$
1827	Is $i = \sqrt{e^{\pi\sqrt{e^{\pi\sqrt\ldots}}}}$?
1828	Example of a compact set that isnt the spectrum of an operator
1829	Why is one $\infty$ number enough for complex numbers?
1830	How do the Catalan numbers turn up here?
1831	What is so special about $\alpha=-1$ in the integral of $x^\alpha$?
1832	To evaluate $\int_0^{+\infty} \frac{\;\mathrm dx}{\sqrt[3]{x^3+a^3}\sqrt[3]{x^3+b^3}\sqrt[3]{x^3+c^3}}$
1833	On a long proof
1834	Why do all the Platonic Solids exist?
1835	Bijection $f\colon\mathbb{N}\to\mathbb{N}$ with $f(0)=0$ and $|f(n)-f(n-1)|=n$
1836	How to solve an nth degree polynomial equation
1837	Number of onto functions
1838	What does := mean?
1839	Adding two polar vectors
1840	Sum of the alternating harmonic series $\sum_{k=1}^{\infty}\frac{(-1)^{k+1}}{k} = \frac{1}{1} - \frac{1}{2} + \cdots $
1841	Average Distance Between Random Points on a Line Segment
1842	Understanding Dot and Cross Product
1843	What are good books/other readings for elementary set theory?
1844	Best Algebraic Topology book/Alternative to Allen Hatcher free book?
1845	What is the implicit function theorem?
1846	What does it mean to integrate with respect to the distribution function?
1847	Very good linear algebra book.
1848	Can a piece of A4 paper be folded so that its thick enough to reach the moon?
1849	Every nonzero element in a finite ring is either a unit or a zero divisor
1850	Projection is an open map
1851	Can someone explain Cayleys Theorem step by step?
1852	Lemma/Proposition/Theorem, which one should we pick?
1853	Game theory - self study
1854	What are the required backgrounds of Robin Hartshornes Algebraic Geometry book?
1855	Semi-direct v.s. Direct products
1856	Why is it that if I count years from 2011 to 2014 as intervals I get 3 years, but if I count each year separately I get 4 years?
1857	What exactly is infinity?
1858	How do we know the ratio between circumference and diameter is the same for all circles?
1859	Good introductory book on geometric algebra
1860	Jacobi identity - intuitive explanation
1861	Why does the volume of the unit sphere go to zero?
1862	Is it possible to place 26 points inside a rectangle that is 20 cm by 15 cm so that the distance between every pair of points is greater than 5 cm?
1863	What does it mean to solve an equation?
1864	Isomorphic quotients by isomorphic normal subgroups
1865	How can this function have two different antiderivatives?
1866	Why arent integration and differentiation inverses of each other?
1867	Is 128 the only multi-digit power of 2 such that each of its digits is also a power of 2?
1868	Do we really need reals?
1869	How can someone reject a math result if everything has to be proved?
1870	What are some things we can prove they must exist, but have no idea what they are?
1871	I dont understand Gödels incompleteness theorem anymore
1872	Where to begin with foundations of mathematics
1873	Development of the Idea of the Determinant
1874	Do we need to formally teach the Greek Alphabet?
1875	The Meaning of the Fundamental Theorem of Calculus
1876	A conjecture involving prime numbers and circles
1877	Is the percentage symbol a constant?
1878	Is a proof still valid if only the writer understands it?
1879	Set Theoretic Definition of Numbers
1880	Why cant Antoines necklace fall apart?
1881	Areas versus volumes of revolution: why does the area require approximation by a cone?
1882	Designing an Irrational Numbers Wall Clock
1883	Must eigenvalues be numbers?
1884	How does the divisibility graphs work?
1885	Axiom of Choice: Where does my argument for proving the axiom of choice fail? Help me understand why this is an axiom, and not a theorem.
1886	The identity cannot be a commutator in a Banach algebra?
1887	If the field of a vector space werent characteristic zero, then what would change in the theory?
1888	What are some math books written in dialogue or story form, e.g., a teacher explaining to a student?
1889	A zero sum subset of a sum-full set
1890	Why cant we define more elementary functions?
1891	A conjectured closed form of $\int\limits_0^\infty\frac{x-1}{\sqrt{2^x-1}\ \ln\left(2^x-1\right)}dx$
1892	Sheldon Cooper Primes
1893	Notations that are mnemonic outside of English
1894	Hidden patterns in $\sin(a x^2)$
1895	AM-GM-HM Triplets
1896	Why is the Galois Correspondence intuitively plausible?
1897	Generalizing the sum of consecutive cubes $\sum_{k=1}^n k^3 = \Big(\sum_{k=1}^n k\Big)^2$ to other odd powers
1898	A curious equality of integrals involving the prime counting function?
1899	Xmas Maths 2015
1900	How to evaluate $\int_0^\infty\operatorname{erfc}^n x\ \mathrm dx$?
1901	Time to reach a final state in a random dynamical system (answer known, proof unknown)
1902	What numbers can be created by $1-x^2$ and $x/2$?
1903	Is there a way to get trig functions without a calculator?
1904	Sample Standard Deviation vs. Population Standard Deviation
1905	Why does an integral change signs when flipping the boundaries?
1906	Why is the absolute value function not differentiable at $x=0$?
1907	Effect of elementary row operations on determinant?
1908	Do all square matrices have eigenvectors?
1909	Is zero a prime number?
1910	How to find a basis for the intersection of two vector spaces in $\mathbb{R}^n$?
1911	Subgroup of index $2$ is Normal
1912	The generating function for the Fibonacci numbers
1913	Examples of infinite groups such that all their respective elements are of finite order.
1914	Why are $3D$ transformation matrices $4 \times 4$ instead of $3 \times 3$?
1915	Show that $\langle 2,x \rangle$ is not a principal ideal in $\mathbb Z [x]$
1916	Every linear mapping on a finite dimensional space is continuous
1917	difference between maximal element and greatest element
1918	How can a set contain itself?
1919	Sum of two closed sets in $\mathbb R$ is closed?
1920	How unique are $U$ and $V$ in the Singular Value Decomposition?
1921	Are normal subgroups transitive?
1922	Why is the ring of matrices over a field simple?
1923	In set theory, how are real numbers represented as sets?
1924	Is it possible to plot a graph of any shape?
1925	Proving $\frac{\sin x}{x} =\left(1-\frac{x^2}{\pi^2}\right)\left(1-\frac{x^2}{2^2\pi^2}\right) \left(1-\frac{x^2}{3^2\pi^2}\right)\cdots$
1926	Subgroups of finitely generated groups are not necessarily finitely generated
1927	$|G|>2$ implies $G$ has non trivial automorphism
1928	There exists a power of 2 such that the last five digits are all 3s or 6s. Find the last 5 digits of this number
1929	Does a Fourier transformation on a (pseudo-)Riemannian manifold make sense?
1930	$\sin 1^\circ$ is irrational but how do I prove it in a slick way? And $\tan(1^\circ)$ is .....
1931	How many fair dice exist?
1932	How to start a math blog?
1933	Modus moron rule of inference?
1934	precise official definition of a cell complex and CW-complex
1935	Alternative proofs that $A_5$ is simple
1936	Can you give me some concrete examples of magmas?
1937	Does Monty Hall logic apply to this real world situation?
1938	Are there dictionaries in math?
1939	How did early mathematicians make it without Set theory?
1940	Sharing a pepperoni pizza with your worst enemy
1941	Is it wrong to tell children that $1/0 =$ NaN is incorrect, and should be $∞$?
1942	Why is the Daniell integral not so popular?
1943	Say $a=b$. Is Do the same thing to both sides of an equation, and it still holds an axiom?
1944	Why is there antagonism towards extended real numbers?
1945	What is a topological space good for?
1946	Are rational points dense on every circle in the coordinate plane?
1947	What do mathematicians mean by equipped?
1948	Category-theoretic limit related to topological limit?
1949	Notation for an interval when you dont know which bound is greater
1950	Why can we use induction when studying metamathematics?
1951	Finding the value of $\sqrt{1+2\sqrt{2+3\sqrt{3+4\sqrt{4+5\sqrt{5+\dots}}}}}$
1952	What if $\pi$ was an algebraic number? (significance of algebraic numbers)
1953	Solution to the equation of a polynomial raised to the power of a polynomial.
1954	Are commutative C*-algebras really dual to locally compact Hausdorff spaces?
1955	Is $dx\,dy$ really a multiplication of $dx$ and $dy$?
1956	Proving $\sum_{n=-\infty}^\infty e^{-\pi n^2} = \frac{\sqrt[4] \pi}{\Gamma\left(\frac 3 4\right)}$
1957	How do you prove Gautschis inequality for the gamma function?
1958	Function that is the sum of all of its derivatives
1959	Identity for simple 1D random walk
1960	Prove $\int\limits_{0}^{\pi/2}\frac{dx}{1+\sin^2{(\tan{x})}}=\frac{\pi}{2\sqrt{2}}\bigl(\frac{e^2+3-2\sqrt{2}}{e^2-3+2\sqrt{2}}\bigr)$
1961	How to maintain enthusiasm and joy in teaching when the material grows stale
1962	An exotic sequence
1963	Making trigonometric substitutions rigorous
1964	A new kind of fractal?
1965	How do you go about doing mathematics on a day to day basis?
1966	$C^{k}$-manifolds: how and why?
1967	Why do I only breathe out of one nostril?
1968	Why are so few foods blue?
1969	Does DNA have the equivalent of IF-statements, WHILE loops, or function calls? How about GOTO?
1970	How many times did terrestrial life emerge from the ocean?
1971	Do bacteria die of old age?
1972	Is there a reason why human eyesight and plants make use of the same wavelength of light?
1973	Why is thymine rather than uracil used in DNA?
1974	Are male and female brains physically different from birth?
1975	What is the effect of non-vaccinated people on vaccinated people?
1976	Why do plants have green leaves and not red?
1977	Can HIV be transmitted via mosquitos?
1978	Whats the evidence against SARS-CoV-2 being engineered by humans?
1979	Do beneficial viruses exist? If so, what examples are there?
1980	Does the string ...CATCAT... appear in the DNA of Felis catus?
1981	Why did the process of sleep evolve in many animals? What is its evolutionary advantage?
1982	Are humans the only species who drink milk as adults?
1983	How could humans have interbred with Neanderthals if were a different species?
1984	Why do some bad traits evolve, and good ones dont?
1985	Death because of distilled water consumption
1986	Why is the heart not in the middle of the body?
1987	Why 20 amino acids instead of 64?
1988	Is there an RGB equivalent for smells?
1989	Whats up with this leaf?
1990	How does the brains energy consumption depend on mental activity?
1991	Do animals exhibit handedness (paw-ness?) preference?
1992	Why do Humans not produce Vitamin C like other mammals?
1993	Why shouldnt dogs eat chocolate?
1994	Why are there no wheeled animals?
1995	What is the evolutionary advantage of red-green color blindness?
1996	Do ants or other insects sleep, and if so why?
1997	What could cause a forest of bent trees?
1998	Is there any evidence that sexual selection may lead to extinction of species?
1999	Why does evolution not make our life longer?
2000	Why does it hurt the next day after doing significant exercise?
2001	Can a woman give birth to twins with different fathers?
2002	Are there organisms with fewer than 1000 neurons?
2003	How come large herbivores have such thin legs?
2004	A new species of small bird?
2005	Why dont mammals have more than 4 limbs?
2006	Why do smaller mammals move intermittently?
2007	Are the social-distancing measures implemented against SARS-CoV-2 also suppressing the spread of other viruses?
2008	Why do the fastest runners tend to be black?
2009	Life without DNA?
2010	What is the benefit of fever during infections?
2011	Why isnt a virus alive?
2012	Why do men have nipples?
2013	Why are there no organisms with metal body parts, like weapons, bones, and armour? (Or are there?)
2014	Human perception of time depending on age
2015	Do large animals experience a meaningful delay when moving their most distant appendages?
2016	Why does cracking a joint make noise?