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100
23,800
Given that $f(x)$ has a derivative and satisfies $\lim_{\Delta x \to 0} \, \frac{f(1)-f(1-2\Delta x)}{2\Delta x}=-1$, find the slope of the tangent line to the curve $y=f(x)$ at the point $(1,f(1))$.
-1
55.46875
23,801
Given a sequence $\{a_n\}$, the first $m(m\geqslant 4)$ terms form an arithmetic sequence with a common difference of $2$. Starting from the $(m-1)$-th term, $a_{m-1}$, $a_{m}$, $a_{m+1}$, ... form a geometric sequence with a common ratio of $2$. If $a_{1}=-2$, then $m=$ ______, and the sum of the first $6$ terms of $\{a_n\}$, $S_{6}=$ ______.
28
68.75
23,802
Given that a hyperbola $\frac{{x}^{2}}{{a}^{2}}-\frac{{y}^{2}}{{b}^{2}}=1$ has only one common point with the parabola $y=x^{2}+1$, calculate the eccentricity of the hyperbola.
\sqrt{5}
29.6875
23,803
Given a sequence $\{a_{n}\}$ where $a_{1}=1$ and $a_{n+1}=\left\{\begin{array}{l}{{a}_{n}+1, n \text{ is odd}}\\{{a}_{n}+2, n \text{ is even}}\end{array}\right.$ $(1)$ Let $b_{n}=a_{2n}$, write down $b_{1}$ and $b_{2}$, and find the general formula for the sequence $\{b_{n}\}$. $(2)$ Find the sum of the first $20$ terms of the sequence $\{a_{n}\}$.
300
73.4375
23,804
Given a sequence ${a_n}$ that satisfies $a_1=1$ and $a_n=a_1+ \frac {1}{2}a_2+ \frac {1}{3}a_3+…+ \frac {1}{n-1}a_{n-1}$ for $n\geqslant 2, n\in\mathbb{N}^*$, if $a_k=2017$, then $k=$ \_\_\_\_\_\_.
4034
56.25
23,805
Define an ordered triple $(D, E, F)$ of sets to be minimally intersecting if $|D \cap E| = |E \cap F| = |F \cap D| = 1$ and $D \cap E \cap F = \emptyset$. Let $M$ be the number of such ordered triples where each set is a subset of $\{1,2,3,4,5,6,7,8\}$. Find $M$ modulo $1000$.
064
0.78125
23,806
Given $$(5x- \frac {1}{ \sqrt {x}})^{n}$$, the sum of the binomial coefficients in its expansion is 64. Find the constant term in the expansion.
375
50
23,807
There is an opaque bag containing 4 identical balls labeled with the numbers 1, 2, 3, and 4. (Ⅰ) If balls are drawn one by one without replacement twice, calculate the probability that the first ball drawn has an even number and the sum of the two balls’ numbers is divisible by 3. (Ⅱ) If a ball is randomly taken from the bag and labeled as a, then put back into the bag, followed by randomly taking another ball, labeled as b, calculate the probability that the line $ax + by + 1 = 0$ has no common points with the circle $x^2 + y^2 = \frac{1}{16}$.
\frac{1}{2}
32.03125
23,808
In $\triangle XYZ$, the medians $\overline{XU}$ and $\overline{YV}$ intersect at right angles. If $XU = 18$ and $YV = 24$, find the area of $\triangle XYZ$.
288
60.9375
23,809
Given the function $f\left(x\right)=\cos \left(\omega x+\varphi \right)\left(\omega\ \ \gt 0,0 \lt \varphi\ \ \lt \pi \right)$, if $f\left(x\right)$ is an odd function and monotonically decreasing on $(-\frac{π}{3},\frac{π}{6})$, then the maximum value of $\omega$ is ______.
\frac{3}{2}
59.375
23,810
Let $T$ be a subset of $\{1,2,3,...,60\}$ such that no pair of distinct elements in $T$ has a sum divisible by $5$. What is the maximum number of elements in $T$?
25
82.8125
23,811
Given the function $f(x)= \sqrt {3}\sin ^{2}x+\sin x\cos x- \frac { \sqrt {3}}{2}$ $(x\in\mathbb{R})$. $(1)$ If $x\in(0, \frac {\pi}{2})$, find the maximum value of $f(x)$; $(2)$ In $\triangle ABC$, if $A < B$ and $f(A)=f(B)= \frac {1}{2}$, find the value of $\frac {BC}{AB}$.
\sqrt {2}
0
23,812
The product of two consecutive page numbers is $2,156.$ What are the sum of these two page numbers?
93
68.75
23,813
What is the largest number of positive, consecutive integers whose sum is 105?
14
22.65625
23,814
In the diagram, three identical circles touch each other, and each circle has a circumference of 24. Calculate the perimeter of the shaded region within the triangle formed by the centers of the circles.
12
5.46875
23,815
Three different numbers are chosen from the set $\{-4, -3, -1, 3, 5, 8\}$ and multiplied. Find the largest possible positive product.
120
95.3125
23,816
Rectangle $ABCD$ is the base of pyramid $PABCD$. If $AB = 10$, $BC = 5$, and the height of the pyramid, $PA$, while not perpendicular to the plane of $ABCD$, ends at the center of rectangle $ABCD$ and is twice the length of $BC$. What is the volume of $PABCD$?
\frac{500}{3}
100
23,817
(For science students) In the expansion of $(x^2 - 3x + 2)^4$, the coefficient of the $x^2$ term is __________ (Answer with a number).
248
75
23,818
Given that $α$ is an angle in the third quadrant and $\cos 2α=-\frac{3}{5}$, find $\tan (\frac{π}{4}+2α)$.
-\frac{1}{7}
10.15625
23,819
Find the value of $m + n$ where $m$ and $n$ are integers such that the positive difference between the roots of the equation $4x^2 - 12x - 9 = 0$ can be expressed as $\frac{\sqrt{m}}{n}$, with $m$ not divisible by the square of any prime number.
19
57.8125
23,820
Consider a dodecahedron, which is made up of 12 pentagonal faces. An ant starts at one of the top vertices and walks to one of the three adjacent vertices (vertex A). From vertex A, the ant walks again to one of its adjacent vertices (vertex B). What is the probability that vertex B is one of the bottom vertices? There are three bottom vertices in total in a dodecahedron.
\frac{1}{3}
27.34375
23,821
Let $x,$ $y,$ $z$ be real numbers such that $x + y + z = 2,$ and $x \ge -\frac{1}{2},$ $y \ge -2,$ and $z \ge -3.$ Find the maximum value of: \[ \sqrt{4x + 2} + \sqrt{4y + 8} + \sqrt{4z + 12}. \]
3\sqrt{10}
1.5625
23,822
Given that $\sin\alpha + \cos\alpha = \frac{1}{5}$, and $0 \leq \alpha < \pi$, find the value of $\tan\alpha$.
- \frac {4}{3}
89.84375
23,823
Walter wakes up at 6:30 a.m., catches the school bus at 7:30 a.m., has 7 classes that last 45 minutes each, enjoys a 30-minute lunch break, and spends an additional 3 hours at school for various activities. He takes the bus home and arrives back at 5:00 p.m. Calculate the total duration of his bus ride.
45
44.53125
23,824
Let $P$ be a point on the hyperbola $\frac{x^{2}}{16} - \frac{y^{2}}{20} = 1$, and let $F_{1}$ and $F_{2}$ be the left and right foci, respectively. If $|PF_{1}| = 9$, then find $|PF_{2}|$.
17
96.09375
23,825
The first 9 positive odd integers are placed in the magic square so that the sum of the numbers in each row, column and diagonal are equal. Find the value of $A + E$ . \[ \begin{tabular}{|c|c|c|}\hline A & 1 & B \hline 5 & C & 13 \hline D & E & 3 \hline\end{tabular} \]
32
82.03125
23,826
The mean of the set of numbers $\{106, 102, 95, 103, 100, y, x\}$ is 104. What is the median of this set of seven numbers?
103
56.25
23,827
Let \[f(x) = \begin{cases} 2x + 4 &\text{if }x<0, \\ 6-3x&\text{if }x\ge 0. \end{cases} \]Find $f(-2)$ and $f(4)$.
-6
67.1875
23,828
Given an arithmetic sequence $\{a_n\}$, the sum of the first $n$ terms is $S_n$. If $\frac{S_6}{S_3} = 3$, then calculate $\frac{S_{12}}{S_{9}}$.
\frac{5}{3}
100
23,829
Given quadrilateral $ABCD$ with diagonals $AC$ and $BD$ intersecting at $O$, $BO=4$, $OD=5$, $AO=9$, $OC=2$, and $AB=7$, find the length of $AD$.
\sqrt{166}
35.9375
23,830
Read the material first, then answer the question. $(1)$ Xiao Zhang encountered a problem when simplifying a quadratic radical: simplify $\sqrt{5-2\sqrt{6}}$. After thinking about it, Xiao Zhang's process of solving this problem is as follows: $\sqrt{5-2\sqrt{6}}=\sqrt{2-2\sqrt{2\times3}+3}$① $=\sqrt{{(\sqrt{2})}^2}-2\sqrt{2}\times\sqrt{3}+{(\sqrt{3})}^2$② $=\sqrt{{(\sqrt{2}-\sqrt{3})}^2}$③ $=\sqrt{2}-\sqrt{3}$④ In the above simplification process, an error occurred in step ____, and the correct result of the simplification is ____; $(2)$ Please simplify $\sqrt{8+4\sqrt{3}}$ based on the inspiration you obtained from the above material.
\sqrt{6}+\sqrt{2}
44.53125
23,831
Solve the following equations using appropriate methods: (1) $x^2=49$; (2) $(2x+3)^2=4(2x+3)$; (3) $2x^2+4x-3=0$ (using the formula method); (4) $(x+8)(x+1)=-12$.
-5
0
23,832
Given the function $f(x)=\frac{1}{2}x^{2}-a\ln x+b$ where $a\in R$. (I) If the equation of the tangent line to the curve $y=f(x)$ at $x=1$ is $3x-y-3=0$, find the values of the real numbers $a$ and $b$. (II) If $x=1$ is the extreme point of the function $f(x)$, find the value of the real number $a$. (III) If $-2\leqslant a < 0$, for any $x_{1}$, $x_{2}\in(0,2]$, the inequality $|f(x_{1})-f(x_{2})|\leqslant m| \frac{1}{x_{1}}- \frac{1}{x_{2}}|$ always holds. Find the minimum value of $m$.
12
7.03125
23,833
Given $\tan (\theta-\pi)=2$, then $\sin ^{2}\theta+\sin \theta\cos \theta-2\cos ^{2}\theta=$ \_\_\_\_\_\_ .
\frac {4}{5}
91.40625
23,834
Anton colors a cell in a \(4 \times 50\) rectangle. He then repeatedly chooses an uncolored cell that is adjacent to at most one already colored cell. What is the maximum number of cells that can be colored?
150
0
23,835
How many positive integer multiples of $77$ (product of $7$ and $11$) can be expressed in the form $10^{j}-10^{i}$, where $i$ and $j$ are integers and $0 \leq i < j \leq 99$?
784
90.625
23,836
Find the value of the arithmetic series $1-3+5-7+9-11+\cdots +2021-2023+2025$.
1013
56.25
23,837
Given a hyperbola $C$ that shares the same foci with the ellipse $\frac{x^{2}}{27}+ \frac{y^{2}}{36}=1$ and passes through the point $(\sqrt{15},4)$. (I) Find the equation of the hyperbola $C$. (II) If $F\_1$ and $F\_2$ are the two foci of the hyperbola $C$, and point $P$ is on the hyperbola $C$ such that $\angle F\_1 P F\_2 = 120^{\circ}$, find the area of $\triangle F\_1 P F\_2$.
\frac{5\sqrt{3}}{3}
21.875
23,838
In triangle ABC, BR = RC, CS = 3SA, and (AT)/(TB) = p/q. If the area of △RST is twice the area of △TBR, determine the value of p/q.
\frac{7}{3}
1.5625
23,839
Calculate the value of \[\cot(\cot^{-1}5 + \cot^{-1}11 + \cot^{-1}17 + \cot^{-1}23).\]
\frac{97}{40}
0
23,840
Given that the random variable X follows a normal distribution N(2, σ²) and P(X≤4)=0.88, find P(0<X<4).
0.76
71.09375
23,841
Given a four-digit positive integer $\overline{abcd}$, if $a+c=b+d=11$, then this number is called a "Shangmei number". Let $f(\overline{abcd})=\frac{{b-d}}{{a-c}}$ and $G(\overline{abcd})=\overline{ab}-\overline{cd}$. For example, for the four-digit positive integer $3586$, since $3+8=11$ and $5+6=11$, $3586$ is a "Shangmei number". Also, $f(3586)=\frac{{5-6}}{{3-8}}=\frac{1}{5}$ and $G(M)=35-86=-51$. If a "Shangmei number" $M$ has its thousands digit less than its hundreds digit, and $G(M)$ is a multiple of $7$, then the minimum value of $f(M)$ is ______.
-3
2.34375
23,842
Let $p$, $q$, $r$, $s$, and $t$ be positive integers with $p+q+r+s+t=2025$ and let $N$ be the largest of the sums $p+q$, $q+r$, $r+s$, and $s+t$. Determine the smallest possible value of $N$.
676
19.53125
23,843
Let the function $f(x)=\ln x- \frac{1}{2}ax^{2}-bx$. $(1)$ When $a=b= \frac{1}{2}$, find the maximum value of the function $f(x)$; $(2)$ Let $F(x)=f(x)+ \frac{1}{2}ax^{2}+bx+ \frac{a}{x}$, $(0 < x\leqslant 3)$, the slope of the tangent line at any point $P(x_{0},y_{0})$ on its graph is $k\leqslant \frac{1}{2}$ always holds, find the range of the real number $a$; $(3)$ When $a=0$, $b=-1$, the equation $2mf(x)=x^{2}$ has a unique real solution, find the value of the positive number $m$.
\frac{1}{2}
15.625
23,844
Use the bisection method to find an approximate solution for $f(x)=0$. Given that $f(1)=-2$, $f(3)=0.625$, and $f(2)=-0.984$, calculate the next $f(m)$, where $m =$ __________.
2.5
35.9375
23,845
(1) If 7 students stand in a row, and students A and B must stand next to each other, how many different arrangements are there? (2) If 7 students stand in a row, and students A, B, and C must not stand next to each other, how many different arrangements are there? (3) If 7 students stand in a row, with student A not standing at the head and student B not standing at the tail, how many different arrangements are there?
3720
89.84375
23,846
Jason wishes to purchase some comic books. He has $15 and each comic book costs $1.20, tax included. Additionally, there is a discount of $0.10 on each comic book if he buys more than 10 comic books. What is the maximum number of comic books he can buy?
12
3.125
23,847
The repeating decimal for $\frac{5}{13}$ is $0.cdc\ldots$ What is the value of the sum $c+d$?
11
87.5
23,848
To solve the problem, we need to find the value of $\log_{4}{\frac{1}{8}}$. A) $-\frac{1}{2}$ B) $-\frac{3}{2}$ C) $\frac{1}{2}$ D) $\frac{3}{2}$
-\frac{3}{2}
92.96875
23,849
Find the sum of $642_8$ and $157_8$ in base $8$.
1021_8
97.65625
23,850
Given that $f(x)$ is a periodic function defined on $\mathbb{R}$ with a period of $2$, when $x \in (-1, 1]$, $f(x)=\begin{cases} -4x^{2}+ \frac{9}{8},-1 < x\leqslant 0, \\ \log _{2}x,0 < x\leqslant 1, \end{cases}$, find the value of $f(f( \frac{7}{2}))=\_\_\_\_\_\_\_\_$.
-3
71.875
23,851
Charlie is planning to construct a boundary around a rectangular playground using exactly 380 feet of fencing. Regulations specify that the length of the boundary must be at least 100 feet and the width must be at least 60 feet. Charlie wants to maximize the area enclosed by the fence for more play equipment and sitting area. What are the optimal dimensions and the maximum possible area of the playground?
9000
71.09375
23,852
Given vectors $\overrightarrow {a}$=(sinx,cosx), $\overrightarrow {b}$=(1,$\sqrt {3}$). (1) If $\overrightarrow {a}$$∥ \overrightarrow {b}$, find the value of tanx; (2) Let f(x) = $\overrightarrow {a}$$$\cdot \overrightarrow {b}$, stretch the horizontal coordinates of each point on the graph of f(x) to twice their original length (vertical coordinates remain unchanged), then shift all points to the left by φ units (0 < φ < π), obtaining the graph of function g(x). If the graph of g(x) is symmetric about the y-axis, find the value of φ.
\frac{\pi}{3}
56.25
23,853
The distance from the point $(3,0)$ to one of the asymptotes of the hyperbola $\frac{{x}^{2}}{16}-\frac{{y}^{2}}{9}=1$ is $\frac{9}{5}$.
\frac{9}{5}
88.28125
23,854
Given the function $f(x)=ax + a^{-x}$ ($a>0$ and $a\neq1$), and $f(1)=3$, find the value of $f(0)+f(1)+f(2)$.
12
57.03125
23,855
If the scores for innovation capability, innovation value, and innovation impact are $8$ points, $9$ points, and $7$ points, respectively, and the total score is calculated based on the ratio of $5:3:2$ for the three scores, calculate the total score of the company.
8.1
76.5625
23,856
Find $x$ such that $\log_x 49 = \log_2 32$.
7^{2/5}
9.375
23,857
Given the hyperbola $C$: $mx^{2}+ny^{2}=1(mn < 0)$, one of its asymptotes is tangent to the circle $x^{2}+y^{2}-6x-2y+9=0$. Determine the eccentricity of $C$.
\dfrac {5}{4}
71.875
23,858
John wants to find all the five-letter words that begin and end with the same letter. How many combinations of letters satisfy this property?
456976
7.03125
23,859
On June 14, 2018, the 21st FIFA World Cup will kick off in Russia. A local sports channel organized fans to guess the outcomes of the matches for the top four popular teams: Germany, Spain, Argentina, and Brazil. Each fan can choose one team from the four, and currently, three people are participating in the guessing game. $(1)$ If each of the three people can choose any team and the selection of each team is equally likely, find the probability that exactly two teams are chosen by people. $(2)$ If one of the three people is a female fan, assuming the probability of the female fan choosing the German team is $\frac{1}{3}$ and the probability of a male fan choosing the German team is $\frac{2}{5}$, let $\xi$ be the number of people choosing the German team among the three. Find the probability distribution and the expected value of $\xi$.
\frac{17}{15}
56.25
23,860
What is the sum of all two-digit positive integers whose squares end with the digits 25?
495
23.4375
23,861
Let \( x, y, z \) be complex numbers such that: \[ xy + 3y = -9, yz + 3z = -9, zx + 3x = -9. \] Determine all possible values of \( xyz \).
27
48.4375
23,862
Find the smallest positive integer that is both an integer power of 7 and is not a palindrome.
2401
7.8125
23,863
Find the sum of the squares of the solutions to the equation \[\left| x^2 - x + \frac{1}{2010} \right| = \frac{1}{2010}.\]
\frac{2008}{1005}
39.84375
23,864
Given an arithmetic sequence $\{a_n\}$, the sum of the first $n$ terms is denoted as $S_n$. If $a_5=5S_5=15$, find the sum of the first $100$ terms of the sequence $\left\{ \frac{1}{a_na_{n+1}} \right\}$.
\frac{100}{101}
5.46875
23,865
If the shortest distance from a point on the ellipse $\frac{y^2}{16} + \frac{x^2}{9} = 1$ to the line $y = x + m$ is $\sqrt{2}$, find the minimum value of $m$.
-7
14.84375
23,866
$ABC$ is triangle. $l_1$ - line passes through $A$ and parallel to $BC$ , $l_2$ - line passes through $C$ and parallel to $AB$ . Bisector of $\angle B$ intersect $l_1$ and $l_2$ at $X,Y$ . $XY=AC$ . What value can take $\angle A- \angle C$ ?
60
20.3125
23,867
If one can find a student with at least $k$ friends in any class which has $21$ students such that at least two of any three of these students are friends, what is the largest possible value of $k$ ?
10
77.34375
23,868
A student named Zhang has a set of 6 questions to choose from, with 4 categorized as type A and 2 as type B. Zhang randomly selects 2 questions to solve. (1) What is the probability that both selected questions are type A? (2) What is the probability that the selected questions are not of the same type?
\frac{8}{15}
66.40625
23,869
We flip a fair coin 12 times. What is the probability that we get exactly 9 heads and all heads occur consecutively?
\dfrac{1}{1024}
70.3125
23,870
Given that Chelsea is ahead by 60 points halfway through a 120-shot archery contest, with each shot scoring 10, 8, 5, 3, or 0 points and Chelsea scoring at least 5 points on every shot, determine the smallest number of bullseyes (10 points) Chelsea needs to shoot in her next n attempts to ensure victory, assuming her opponent can score a maximum of 10 points on each remaining shot.
49
38.28125
23,871
Cagney can frost a cupcake every 15 seconds, while Lacey can frost every 40 seconds. They take a 10-second break after every 10 cupcakes. Calculate the number of cupcakes that they can frost together in 10 minutes.
50
7.03125
23,872
We need to arrange the performance order for 4 singing programs and 2 skit programs. The requirement is that there must be exactly 3 singing programs between the 2 skit programs. The number of possible arrangements is \_\_\_\_\_\_ . (Answer with a number)
96
43.75
23,873
Triangle $PQR$ has side lengths $PQ=6$, $QR=8$, and $PR=9$. Two bugs start simultaneously from $P$ and crawl along the perimeter of the triangle in opposite directions at the same speed. They meet at point $S$. What is $QS$?
5.5
66.40625
23,874
Given $f(x) = \sin x + a\cos x$, (1) If $a= \sqrt{3}$, find the maximum value of $f(x)$ and the corresponding value of $x$. (2) If $f\left(\frac{\pi}{4}\right) = 0$ and $f(x) = \frac{1}{5}$ $(0 < x < \pi)$, find the value of $\tan x$.
\frac{4}{3}
74.21875
23,875
In the Cartesian coordinate system $xOy$, the parametric equation of line $l$ is given by $$\begin{cases} x= \dfrac { \sqrt {2}}{2}t \\ y= \dfrac { \sqrt {2}}{2}t+4 \sqrt {2} \end{cases} (t \text{ is the parameter}),$$ establishing a polar coordinate system with the origin as the pole and the positive x-axis as the polar axis, the polar equation of circle $C$ is $ρ=2\cos \left(θ+ \dfrac {π}{4}\right)$. (Ⅰ) Find the Cartesian coordinates of the center $C$ of the circle; (Ⅱ) From any point on line $l$, draw a tangent to the circle $C$, and find the minimum length of the tangent line.
2 \sqrt {6}
0
23,876
Four different balls are to be placed into five boxes numbered 1, 2, 3, 4, and 5. (Write the result as a number) (1) How many ways can there be with at least one ball in box number 1? (2) How many ways are there to have exactly two empty boxes? (3) How many ways are there to have exactly three empty boxes? (4) How many ways are there such that the box number containing ball A is not less than the box number containing ball B?
375
29.6875
23,877
Given that the merchant purchased $1200$ keychains at $0.15$ each and desired to reach a target profit of $180$, determine the minimum number of keychains the merchant must sell if each is sold for $0.45$.
800
31.25
23,878
Given a sequence $\{a\_n\}$ that satisfies $a\_1=1$ and $a\_n= \frac{2S\_n^2}{2S\_n-1}$ for $n\geqslant 2$, where $S\_n$ is the sum of the first $n$ terms of the sequence, find the value of $S\_{2016}$.
\frac{1}{4031}
82.8125
23,879
In response to the national medical and health system reform and the "Three Visits to the Countryside" cultural and scientific activities nationwide in 2023, to truly implement the concept of "putting the people first" and promote the transfer and decentralization of high-quality medical resources, continuously enhance the "depth" and "warmth" of medical services. The People's Hospital of our city plans to select 3 doctors from the 6 doctors recommended by each department to participate in the activity of "Healthy Countryside Visit, Free Clinic Warming Hearts." Among these 6 doctors, there are 2 surgeons, 2 internists, and 2 ophthalmologists. - $(1)$ Find the probability that the number of selected surgeons is greater than the number of selected internists. - $(2)$ Let $X$ represent the number of surgeons selected out of the 3 people. Find the mean and variance of $X$.
\frac{2}{5}
79.6875
23,880
Given the word 'ARROW', find the probability that a random arrangement of its letters will have both R's next to each other.
\frac{2}{5}
84.375
23,881
Given Harry has 4 sisters and 6 brothers, and his sister Harriet has S sisters and B brothers, calculate the product of S and B.
24
17.1875
23,882
Given a periodic sequence $\left\{x_{n}\right\}$ that satisfies $x_{n}=\left|x_{n-1}-x_{n-2}\right|(n \geqslant 3)$, if $x_{1}=1$ and $x_{2}=a \geqslant 0$, calculate the sum of the first 2002 terms when the period of the sequence is minimized.
1335
85.9375
23,883
Using systematic sampling to select 20 students from 1000, the students are randomly numbered from 000 to 999 and grouped: the first group ranges from 000 to 049, the second group from 050 to 099, ..., and the twentieth group from 950 to 999. If the number 122 from the third group is selected, then the number of the student selected in the eighteenth group would be: ______.
872
88.28125
23,884
Given the function $f(x)=2\sin x\cos x+2 \sqrt {3}\cos ^{2}x- \sqrt {3}$, where $x\in\mathbb{R}$. (Ⅰ) Find the smallest positive period and the intervals of monotonic decrease for the function $y=f(-3x)+1$; (Ⅱ) Given in $\triangle ABC$, the sides opposite to angles $A$, $B$, and $C$ are $a$, $b$, and $c$ respectively. If the acute angle $A$ satisfies $f\left( \frac {A}{2}- \frac {\pi}{6}\right)= \sqrt {3}$, and $a=7$, $\sin B+\sin C= \frac {13 \sqrt {3}}{14}$, find the area of $\triangle ABC$.
10 \sqrt {3}
0
23,885
On a bustling street, a middle-aged man is shouting "giving away money" while holding a small black cloth bag in his hand. Inside the bag, there are 3 yellow and 3 white ping-pong balls (which are identical in volume and texture). Next to him, there's a small blackboard stating: Method of drawing balls: Randomly draw 3 balls from the bag. If the 3 balls drawn are of the same color, the stall owner will give the drawer $10; if the 3 balls drawn are not of the same color, the drawer will pay the stall owner $2. (1) What is the probability of drawing 3 yellow balls? (2) What is the probability of drawing 2 yellow balls and 1 white ball? (3) Assuming there are 80 draws per day, estimate how much money the stall owner can make in a month (30 days) from a probabilistic perspective?
1920
24.21875
23,886
There are 3 small balls of each of the red, yellow, and blue colors, with the same size. Each of the 3 balls of each color is marked with numbers 1, 2, and 3. If 3 balls are randomly drawn, find the probability that neither their colors nor their numbers are the same.
\frac{1}{14}
12.5
23,887
If the function $f\left(x\right)=\frac{1}{2}\left(m-2\right){x}^{2}+\left(n-8\right)x+1\left(m\geqslant 0,n\geqslant 0\right)$ is monotonically decreasing in the interval $\left[\frac{1}{2},2\right]$, find the maximum value of $mn$.
18
29.6875
23,888
In a geometric sequence $\{a_n\}$, it is known that $a_1 = -2$ and $S_3 = -\frac{7}{2}$. Then, the common ratio $q$ equals \_\_\_\_\_\_ .
-\frac{3}{2}
27.34375
23,889
Given that $m$ is a positive integer, and given that $\mathop{\text{lcm}}[40,m]=120$ and $\mathop{\text{lcm}}[m,45]=180$, what is $m$?
60
76.5625
23,890
Given that the scores X of 10000 people approximately follow a normal distribution N(100,13^2), it is given that P(61 < X < 139)=0.997, find the number of people scoring no less than 139 points in this exam.
15
60.15625
23,891
Chloe chooses a real number uniformly at random from the interval $[0, 3000]$. Independently, Max chooses a real number uniformly at random from the interval $[0, 4500]$. Determine the probability that Max's number is at least twice as large as Chloe's number.
\frac{3}{8}
7.8125
23,892
Humanity finds 12 habitable planets, of which 6 are Earth-like and 6 are Mars-like. Earth-like planets require 3 units of colonization resources, while Mars-like need 1 unit. If 18 units of colonization resources are available, how many different combinations of planets can be colonized, assuming each planet is unique?
136
7.8125
23,893
If $x = 151$ and $x^3y - 3x^2y + 3xy = 3423000$, what is the value of $y$?
\frac{3423000}{3375001}
0.78125
23,894
In a batch of 100 products, there are 98 qualified products and 2 defective ones. During product inspection, 3 products are randomly selected from the 100 products. (1) How many different ways are there to select the 3 products? (2) How many ways are there to select exactly 1 defective product out of the 3? (3) How many ways are there to select at least 1 defective product out of the 3?
9604
96.09375
23,895
Given the cyclist encounters red lights at each of 4 intersections with probability $\frac{1}{3}$ and the events of encountering red lights are independent, calculate the probability that the cyclist does not encounter red lights at the first two intersections and encounters the first red light at the third intersection.
\frac{4}{27}
78.125
23,896
Let $m > n$ be positive integers such that $3(3mn - 2)^2 - 2(3m -3n)^2 = 2019$ . Find $3m + n$ .
46
83.59375
23,897
Given the sequence $\{a_n\}$ where $a_n > 0$, $a_1=1$, $a_{n+2}= \frac {1}{a_n+1}$, and $a_{100}=a_{96}$, find the value of $a_{2014}+a_3$.
\frac{\sqrt{5}}{2}
37.5
23,898
Given $0 < \beta < \alpha < \frac{\pi}{2}$, point $P(1,4 \sqrt{3})$ is a point on the terminal side of angle $\alpha$, and $\sin \alpha \sin \left(\frac{\pi}{2}-\beta \right)+\cos \alpha \cos \left(\frac{\pi}{2}+\beta \right)= \frac{3 \sqrt{3}}{14}$, calculate the value of angle $\beta$.
\frac{\pi}{3}
64.84375
23,899
Calculate the area, in square units, of the triangle formed by the $x$ and $y$ intercepts of the curve $y = (x-3)^2 (x+2) (x-1)$.
45
68.75