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5518-5521
( ) c a b c c + r+ r r r r = 2 2 2 | | | | | | a b c + + r r r = 9 + 16 + 25 = 50 Therefore | | a b c + r+ r r = 50 5 2 = © NCERT not to be republished VECTOR ALGEBRA 457 Example 29 Three vectors , and a b c r r r satisfy the condition 0 a b c + + = r r r r Evaluate the quantity , if | | 1, | | 4 and | | 2 a b b c c a a b c μ = ⋅ + ⋅ + ⋅ = = = r r r r r r r r r Solution Since 0 a b c + + = r r r r , we have ( ) a a b c r r r r = 0 or a a a b a c ⋅ + ⋅ + ⋅ r r r r r r = 0 Therefore a b a c ⋅ + ⋅ r r r r = 2 1 −a = − r
1
5519-5522
c a b c c + r+ r r r r = 2 2 2 | | | | | | a b c + + r r r = 9 + 16 + 25 = 50 Therefore | | a b c + r+ r r = 50 5 2 = © NCERT not to be republished VECTOR ALGEBRA 457 Example 29 Three vectors , and a b c r r r satisfy the condition 0 a b c + + = r r r r Evaluate the quantity , if | | 1, | | 4 and | | 2 a b b c c a a b c μ = ⋅ + ⋅ + ⋅ = = = r r r r r r r r r Solution Since 0 a b c + + = r r r r , we have ( ) a a b c r r r r = 0 or a a a b a c ⋅ + ⋅ + ⋅ r r r r r r = 0 Therefore a b a c ⋅ + ⋅ r r r r = 2 1 −a = − r (1) Again, ( ) b a b c ⋅ + + r r r r = 0 or a b b c ⋅ + ⋅ r r r r = 2 16 −b = − r
1
5520-5523
Evaluate the quantity , if | | 1, | | 4 and | | 2 a b b c c a a b c μ = ⋅ + ⋅ + ⋅ = = = r r r r r r r r r Solution Since 0 a b c + + = r r r r , we have ( ) a a b c r r r r = 0 or a a a b a c ⋅ + ⋅ + ⋅ r r r r r r = 0 Therefore a b a c ⋅ + ⋅ r r r r = 2 1 −a = − r (1) Again, ( ) b a b c ⋅ + + r r r r = 0 or a b b c ⋅ + ⋅ r r r r = 2 16 −b = − r (2) Similarly a c b c ⋅ + r⋅ r r r = – 4
1
5521-5524
Solution Since 0 a b c + + = r r r r , we have ( ) a a b c r r r r = 0 or a a a b a c ⋅ + ⋅ + ⋅ r r r r r r = 0 Therefore a b a c ⋅ + ⋅ r r r r = 2 1 −a = − r (1) Again, ( ) b a b c ⋅ + + r r r r = 0 or a b b c ⋅ + ⋅ r r r r = 2 16 −b = − r (2) Similarly a c b c ⋅ + r⋅ r r r = – 4 (3) Adding (1), (2) and (3), we have 2 ( ) a b b a c c ⋅ + ⋅ + ⋅ r r r r r r = – 21 or 2μ = – 21, i
1
5522-5525
(1) Again, ( ) b a b c ⋅ + + r r r r = 0 or a b b c ⋅ + ⋅ r r r r = 2 16 −b = − r (2) Similarly a c b c ⋅ + r⋅ r r r = – 4 (3) Adding (1), (2) and (3), we have 2 ( ) a b b a c c ⋅ + ⋅ + ⋅ r r r r r r = – 21 or 2μ = – 21, i e
1
5523-5526
(2) Similarly a c b c ⋅ + r⋅ r r r = – 4 (3) Adding (1), (2) and (3), we have 2 ( ) a b b a c c ⋅ + ⋅ + ⋅ r r r r r r = – 21 or 2μ = – 21, i e , μ = 221 − Example 30 If with reference to the right handed system of mutually perpendicular unit vectors ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ , and , 3 , 2 – 3 i j k i j i j k α = − β = + r r , then express β r in the form 1 2 , where 1 r r r r is parallel to and 2 r r is perpendicular to αr
1
5524-5527
(3) Adding (1), (2) and (3), we have 2 ( ) a b b a c c ⋅ + ⋅ + ⋅ r r r r r r = – 21 or 2μ = – 21, i e , μ = 221 − Example 30 If with reference to the right handed system of mutually perpendicular unit vectors ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ , and , 3 , 2 – 3 i j k i j i j k α = − β = + r r , then express β r in the form 1 2 , where 1 r r r r is parallel to and 2 r r is perpendicular to αr Solution Let 1 , r r is a scalar, i
1
5525-5528
e , μ = 221 − Example 30 If with reference to the right handed system of mutually perpendicular unit vectors ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ , and , 3 , 2 – 3 i j k i j i j k α = − β = + r r , then express β r in the form 1 2 , where 1 r r r r is parallel to and 2 r r is perpendicular to αr Solution Let 1 , r r is a scalar, i e
1
5526-5529
, μ = 221 − Example 30 If with reference to the right handed system of mutually perpendicular unit vectors ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ , and , 3 , 2 – 3 i j k i j i j k α = − β = + r r , then express β r in the form 1 2 , where 1 r r r r is parallel to and 2 r r is perpendicular to αr Solution Let 1 , r r is a scalar, i e , 1 ˆ ˆ 3 i rβ = λ − λj
1
5527-5530
Solution Let 1 , r r is a scalar, i e , 1 ˆ ˆ 3 i rβ = λ − λj Now 2 rβ = β −β1 r r = ˆ ˆ ˆ (2 3 ) (1 ) 3 i j k − λ + + λ −
1
5528-5531
e , 1 ˆ ˆ 3 i rβ = λ − λj Now 2 rβ = β −β1 r r = ˆ ˆ ˆ (2 3 ) (1 ) 3 i j k − λ + + λ − Now, since β2 r is to be perpendicular to αr , we should have 2 α⋅β =0 rr
1
5529-5532
, 1 ˆ ˆ 3 i rβ = λ − λj Now 2 rβ = β −β1 r r = ˆ ˆ ˆ (2 3 ) (1 ) 3 i j k − λ + + λ − Now, since β2 r is to be perpendicular to αr , we should have 2 α⋅β =0 rr i
1
5530-5533
Now 2 rβ = β −β1 r r = ˆ ˆ ˆ (2 3 ) (1 ) 3 i j k − λ + + λ − Now, since β2 r is to be perpendicular to αr , we should have 2 α⋅β =0 rr i e
1
5531-5534
Now, since β2 r is to be perpendicular to αr , we should have 2 α⋅β =0 rr i e , 3(2 3 ) (1 ) − λ − + λ = 0 or λ = 1 2 Therefore β1 r = 3 1 ˆ ˆ 2 2 i j − and 2 1 3 ˆ ˆ ˆ – 3 2 2 i j k β = + r © NCERT not to be republished MATHEMATICS 458 Miscellaneous Exercise on Chapter 10 1
1
5532-5535
i e , 3(2 3 ) (1 ) − λ − + λ = 0 or λ = 1 2 Therefore β1 r = 3 1 ˆ ˆ 2 2 i j − and 2 1 3 ˆ ˆ ˆ – 3 2 2 i j k β = + r © NCERT not to be republished MATHEMATICS 458 Miscellaneous Exercise on Chapter 10 1 Write down a unit vector in XY-plane, making an angle of 30° with the positive direction of x-axis
1
5533-5536
e , 3(2 3 ) (1 ) − λ − + λ = 0 or λ = 1 2 Therefore β1 r = 3 1 ˆ ˆ 2 2 i j − and 2 1 3 ˆ ˆ ˆ – 3 2 2 i j k β = + r © NCERT not to be republished MATHEMATICS 458 Miscellaneous Exercise on Chapter 10 1 Write down a unit vector in XY-plane, making an angle of 30° with the positive direction of x-axis 2
1
5534-5537
, 3(2 3 ) (1 ) − λ − + λ = 0 or λ = 1 2 Therefore β1 r = 3 1 ˆ ˆ 2 2 i j − and 2 1 3 ˆ ˆ ˆ – 3 2 2 i j k β = + r © NCERT not to be republished MATHEMATICS 458 Miscellaneous Exercise on Chapter 10 1 Write down a unit vector in XY-plane, making an angle of 30° with the positive direction of x-axis 2 Find the scalar components and magnitude of the vector joining the points P(x1, y1, z1) and Q(x2, y2, z2)
1
5535-5538
Write down a unit vector in XY-plane, making an angle of 30° with the positive direction of x-axis 2 Find the scalar components and magnitude of the vector joining the points P(x1, y1, z1) and Q(x2, y2, z2) 3
1
5536-5539
2 Find the scalar components and magnitude of the vector joining the points P(x1, y1, z1) and Q(x2, y2, z2) 3 A girl walks 4 km towards west, then she walks 3 km in a direction 30° east of north and stops
1
5537-5540
Find the scalar components and magnitude of the vector joining the points P(x1, y1, z1) and Q(x2, y2, z2) 3 A girl walks 4 km towards west, then she walks 3 km in a direction 30° east of north and stops Determine the girl’s displacement from her initial point of departure
1
5538-5541
3 A girl walks 4 km towards west, then she walks 3 km in a direction 30° east of north and stops Determine the girl’s displacement from her initial point of departure 4
1
5539-5542
A girl walks 4 km towards west, then she walks 3 km in a direction 30° east of north and stops Determine the girl’s displacement from her initial point of departure 4 If a b c = r+ r r , then is it true that | | | | | | a b c = + r r r
1
5540-5543
Determine the girl’s displacement from her initial point of departure 4 If a b c = r+ r r , then is it true that | | | | | | a b c = + r r r Justify your answer
1
5541-5544
4 If a b c = r+ r r , then is it true that | | | | | | a b c = + r r r Justify your answer 5
1
5542-5545
If a b c = r+ r r , then is it true that | | | | | | a b c = + r r r Justify your answer 5 Find the value of x for which ˆ ˆ ˆ ( ) x i j k + + is a unit vector
1
5543-5546
Justify your answer 5 Find the value of x for which ˆ ˆ ˆ ( ) x i j k + + is a unit vector 6
1
5544-5547
5 Find the value of x for which ˆ ˆ ˆ ( ) x i j k + + is a unit vector 6 Find a vector of magnitude 5 units, and parallel to the resultant of the vectors ˆ ˆ ˆ ˆ ˆ ˆ 2 3 and 2 a i j k b i j k = + − = − + r r
1
5545-5548
Find the value of x for which ˆ ˆ ˆ ( ) x i j k + + is a unit vector 6 Find a vector of magnitude 5 units, and parallel to the resultant of the vectors ˆ ˆ ˆ ˆ ˆ ˆ 2 3 and 2 a i j k b i j k = + − = − + r r 7
1
5546-5549
6 Find a vector of magnitude 5 units, and parallel to the resultant of the vectors ˆ ˆ ˆ ˆ ˆ ˆ 2 3 and 2 a i j k b i j k = + − = − + r r 7 If ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ , 2 3 and 2 a i j k b i j k c i j k = + + = − + = − + r r r , find a unit vector parallel to the vector 2 – 3 a b r+c r r
1
5547-5550
Find a vector of magnitude 5 units, and parallel to the resultant of the vectors ˆ ˆ ˆ ˆ ˆ ˆ 2 3 and 2 a i j k b i j k = + − = − + r r 7 If ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ , 2 3 and 2 a i j k b i j k c i j k = + + = − + = − + r r r , find a unit vector parallel to the vector 2 – 3 a b r+c r r 8
1
5548-5551
7 If ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ , 2 3 and 2 a i j k b i j k c i j k = + + = − + = − + r r r , find a unit vector parallel to the vector 2 – 3 a b r+c r r 8 Show that the points A(1, – 2, – 8), B(5, 0, –2) and C(11, 3, 7) are collinear, and find the ratio in which B divides AC
1
5549-5552
If ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ , 2 3 and 2 a i j k b i j k c i j k = + + = − + = − + r r r , find a unit vector parallel to the vector 2 – 3 a b r+c r r 8 Show that the points A(1, – 2, – 8), B(5, 0, –2) and C(11, 3, 7) are collinear, and find the ratio in which B divides AC 9
1
5550-5553
8 Show that the points A(1, – 2, – 8), B(5, 0, –2) and C(11, 3, 7) are collinear, and find the ratio in which B divides AC 9 Find the position vector of a point R which divides the line joining two points P and Q whose position vectors are (2 ) and ( – 3 ) a b a b + r r r r externally in the ratio 1 : 2
1
5551-5554
Show that the points A(1, – 2, – 8), B(5, 0, –2) and C(11, 3, 7) are collinear, and find the ratio in which B divides AC 9 Find the position vector of a point R which divides the line joining two points P and Q whose position vectors are (2 ) and ( – 3 ) a b a b + r r r r externally in the ratio 1 : 2 Also, show that P is the mid point of the line segment RQ
1
5552-5555
9 Find the position vector of a point R which divides the line joining two points P and Q whose position vectors are (2 ) and ( – 3 ) a b a b + r r r r externally in the ratio 1 : 2 Also, show that P is the mid point of the line segment RQ 10
1
5553-5556
Find the position vector of a point R which divides the line joining two points P and Q whose position vectors are (2 ) and ( – 3 ) a b a b + r r r r externally in the ratio 1 : 2 Also, show that P is the mid point of the line segment RQ 10 The two adjacent sides of a parallelogram are ˆ ˆ ˆ ˆ ˆ ˆ 2 4 5 and 2 3 i j k i j k − + − −
1
5554-5557
Also, show that P is the mid point of the line segment RQ 10 The two adjacent sides of a parallelogram are ˆ ˆ ˆ ˆ ˆ ˆ 2 4 5 and 2 3 i j k i j k − + − − Find the unit vector parallel to its diagonal
1
5555-5558
10 The two adjacent sides of a parallelogram are ˆ ˆ ˆ ˆ ˆ ˆ 2 4 5 and 2 3 i j k i j k − + − − Find the unit vector parallel to its diagonal Also, find its area
1
5556-5559
The two adjacent sides of a parallelogram are ˆ ˆ ˆ ˆ ˆ ˆ 2 4 5 and 2 3 i j k i j k − + − − Find the unit vector parallel to its diagonal Also, find its area 11
1
5557-5560
Find the unit vector parallel to its diagonal Also, find its area 11 Show that the direction cosines of a vector equally inclined to the axes OX, OY and OZ are 1 1 1 , ,
1
5558-5561
Also, find its area 11 Show that the direction cosines of a vector equally inclined to the axes OX, OY and OZ are 1 1 1 , , 3 3 3 12
1
5559-5562
11 Show that the direction cosines of a vector equally inclined to the axes OX, OY and OZ are 1 1 1 , , 3 3 3 12 Let ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ 4 2 , 3 2 7 and 2 4 a i j k b i j k c i j k = + + = − + = − + r r r
1
5560-5563
Show that the direction cosines of a vector equally inclined to the axes OX, OY and OZ are 1 1 1 , , 3 3 3 12 Let ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ 4 2 , 3 2 7 and 2 4 a i j k b i j k c i j k = + + = − + = − + r r r Find a vector d r which is perpendicular to both a and rb r , and 15 c d ⋅ rr=
1
5561-5564
3 3 3 12 Let ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ 4 2 , 3 2 7 and 2 4 a i j k b i j k c i j k = + + = − + = − + r r r Find a vector d r which is perpendicular to both a and rb r , and 15 c d ⋅ rr= 13
1
5562-5565
Let ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ 4 2 , 3 2 7 and 2 4 a i j k b i j k c i j k = + + = − + = − + r r r Find a vector d r which is perpendicular to both a and rb r , and 15 c d ⋅ rr= 13 The scalar product of the vector ˆ ˆ ˆ i j k + + with a unit vector along the sum of vectors ˆ ˆ ˆ 2 4 5 i j k + − and ˆ ˆ 2ˆ 3 i j k λ + + is equal to one
1
5563-5566
Find a vector d r which is perpendicular to both a and rb r , and 15 c d ⋅ rr= 13 The scalar product of the vector ˆ ˆ ˆ i j k + + with a unit vector along the sum of vectors ˆ ˆ ˆ 2 4 5 i j k + − and ˆ ˆ 2ˆ 3 i j k λ + + is equal to one Find the value of λ
1
5564-5567
13 The scalar product of the vector ˆ ˆ ˆ i j k + + with a unit vector along the sum of vectors ˆ ˆ ˆ 2 4 5 i j k + − and ˆ ˆ 2ˆ 3 i j k λ + + is equal to one Find the value of λ 14
1
5565-5568
The scalar product of the vector ˆ ˆ ˆ i j k + + with a unit vector along the sum of vectors ˆ ˆ ˆ 2 4 5 i j k + − and ˆ ˆ 2ˆ 3 i j k λ + + is equal to one Find the value of λ 14 If , a b, c r r r are mutually perpendicular vectors of equal magnitudes, show that the vector a b c + r+ r r is equally inclined to , and a b c r r r
1
5566-5569
Find the value of λ 14 If , a b, c r r r are mutually perpendicular vectors of equal magnitudes, show that the vector a b c + r+ r r is equally inclined to , and a b c r r r © NCERT not to be republished VECTOR ALGEBRA 459 15
1
5567-5570
14 If , a b, c r r r are mutually perpendicular vectors of equal magnitudes, show that the vector a b c + r+ r r is equally inclined to , and a b c r r r © NCERT not to be republished VECTOR ALGEBRA 459 15 Prove that 2 2 ( ) ( ) | | | | a b a b a b + ⋅ + = + r r r r r r , if and only if ,a b rr are perpendicular, given 0, 0 a b ≠ rr≠ r r
1
5568-5571
If , a b, c r r r are mutually perpendicular vectors of equal magnitudes, show that the vector a b c + r+ r r is equally inclined to , and a b c r r r © NCERT not to be republished VECTOR ALGEBRA 459 15 Prove that 2 2 ( ) ( ) | | | | a b a b a b + ⋅ + = + r r r r r r , if and only if ,a b rr are perpendicular, given 0, 0 a b ≠ rr≠ r r Choose the correct answer in Exercises 16 to 19
1
5569-5572
© NCERT not to be republished VECTOR ALGEBRA 459 15 Prove that 2 2 ( ) ( ) | | | | a b a b a b + ⋅ + = + r r r r r r , if and only if ,a b rr are perpendicular, given 0, 0 a b ≠ rr≠ r r Choose the correct answer in Exercises 16 to 19 16
1
5570-5573
Prove that 2 2 ( ) ( ) | | | | a b a b a b + ⋅ + = + r r r r r r , if and only if ,a b rr are perpendicular, given 0, 0 a b ≠ rr≠ r r Choose the correct answer in Exercises 16 to 19 16 If θ is the angle between two vectors a and rb r , then 0 a b ⋅ rr≥ only when (A) 0 < θ <π2 (B) 0 π2 ≤ θ ≤ (C) 0 < θ < π (D) 0 ≤ θ ≤ π 17
1
5571-5574
Choose the correct answer in Exercises 16 to 19 16 If θ is the angle between two vectors a and rb r , then 0 a b ⋅ rr≥ only when (A) 0 < θ <π2 (B) 0 π2 ≤ θ ≤ (C) 0 < θ < π (D) 0 ≤ θ ≤ π 17 Let and a rb r be two unit vectors and θ is the angle between them
1
5572-5575
16 If θ is the angle between two vectors a and rb r , then 0 a b ⋅ rr≥ only when (A) 0 < θ <π2 (B) 0 π2 ≤ θ ≤ (C) 0 < θ < π (D) 0 ≤ θ ≤ π 17 Let and a rb r be two unit vectors and θ is the angle between them Then a +b r r is a unit vector if (A) θ =π4 (B) θ =π3 (C) θ =π2 (D) π32 θ = 18
1
5573-5576
If θ is the angle between two vectors a and rb r , then 0 a b ⋅ rr≥ only when (A) 0 < θ <π2 (B) 0 π2 ≤ θ ≤ (C) 0 < θ < π (D) 0 ≤ θ ≤ π 17 Let and a rb r be two unit vectors and θ is the angle between them Then a +b r r is a unit vector if (A) θ =π4 (B) θ =π3 (C) θ =π2 (D) π32 θ = 18 The value of ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ
1
5574-5577
Let and a rb r be two unit vectors and θ is the angle between them Then a +b r r is a unit vector if (A) θ =π4 (B) θ =π3 (C) θ =π2 (D) π32 θ = 18 The value of ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ( ) ( ) ( ) i j k j i k k i j is (A) 0 (B) –1 (C) 1 (D) 3 19
1
5575-5578
Then a +b r r is a unit vector if (A) θ =π4 (B) θ =π3 (C) θ =π2 (D) π32 θ = 18 The value of ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ( ) ( ) ( ) i j k j i k k i j is (A) 0 (B) –1 (C) 1 (D) 3 19 If θ is the angle between any two vectors and a rb r , then | | | | a b a b ⋅ = × r r r r when θ is equal to (A) 0 (B) π4 (C) π2 (D) π Summary � Position vector of a point P(x, y, z) is given as ˆ ˆ ˆ OP( r) xi yj zk = = + + uuur r , and its magnitude by 2 2 2 x y z + +
1
5576-5579
The value of ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ( ) ( ) ( ) i j k j i k k i j is (A) 0 (B) –1 (C) 1 (D) 3 19 If θ is the angle between any two vectors and a rb r , then | | | | a b a b ⋅ = × r r r r when θ is equal to (A) 0 (B) π4 (C) π2 (D) π Summary � Position vector of a point P(x, y, z) is given as ˆ ˆ ˆ OP( r) xi yj zk = = + + uuur r , and its magnitude by 2 2 2 x y z + + � The scalar components of a vector are its direction ratios, and represent its projections along the respective axes
1
5577-5580
( ) ( ) ( ) i j k j i k k i j is (A) 0 (B) –1 (C) 1 (D) 3 19 If θ is the angle between any two vectors and a rb r , then | | | | a b a b ⋅ = × r r r r when θ is equal to (A) 0 (B) π4 (C) π2 (D) π Summary � Position vector of a point P(x, y, z) is given as ˆ ˆ ˆ OP( r) xi yj zk = = + + uuur r , and its magnitude by 2 2 2 x y z + + � The scalar components of a vector are its direction ratios, and represent its projections along the respective axes � The magnitude (r), direction ratios (a, b, c) and direction cosines (l, m, n) of any vector are related as: , , a b c l m n r r r = = = � The vector sum of the three sides of a triangle taken in order is 0 r
1
5578-5581
If θ is the angle between any two vectors and a rb r , then | | | | a b a b ⋅ = × r r r r when θ is equal to (A) 0 (B) π4 (C) π2 (D) π Summary � Position vector of a point P(x, y, z) is given as ˆ ˆ ˆ OP( r) xi yj zk = = + + uuur r , and its magnitude by 2 2 2 x y z + + � The scalar components of a vector are its direction ratios, and represent its projections along the respective axes � The magnitude (r), direction ratios (a, b, c) and direction cosines (l, m, n) of any vector are related as: , , a b c l m n r r r = = = � The vector sum of the three sides of a triangle taken in order is 0 r © NCERT not to be republished MATHEMATICS 460 � The vector sum of two coinitial vectors is given by the diagonal of the parallelogram whose adjacent sides are the given vectors
1
5579-5582
� The scalar components of a vector are its direction ratios, and represent its projections along the respective axes � The magnitude (r), direction ratios (a, b, c) and direction cosines (l, m, n) of any vector are related as: , , a b c l m n r r r = = = � The vector sum of the three sides of a triangle taken in order is 0 r © NCERT not to be republished MATHEMATICS 460 � The vector sum of two coinitial vectors is given by the diagonal of the parallelogram whose adjacent sides are the given vectors � The multiplication of a given vector by a scalar λ, changes the magnitude of the vector by the multiple |λ|, and keeps the direction same (or makes it opposite) according as the value of λ is positive (or negative)
1
5580-5583
� The magnitude (r), direction ratios (a, b, c) and direction cosines (l, m, n) of any vector are related as: , , a b c l m n r r r = = = � The vector sum of the three sides of a triangle taken in order is 0 r © NCERT not to be republished MATHEMATICS 460 � The vector sum of two coinitial vectors is given by the diagonal of the parallelogram whose adjacent sides are the given vectors � The multiplication of a given vector by a scalar λ, changes the magnitude of the vector by the multiple |λ|, and keeps the direction same (or makes it opposite) according as the value of λ is positive (or negative) � For a given vector ar , the vector ˆ | a| a =a r r gives the unit vector in the direction of ar
1
5581-5584
© NCERT not to be republished MATHEMATICS 460 � The vector sum of two coinitial vectors is given by the diagonal of the parallelogram whose adjacent sides are the given vectors � The multiplication of a given vector by a scalar λ, changes the magnitude of the vector by the multiple |λ|, and keeps the direction same (or makes it opposite) according as the value of λ is positive (or negative) � For a given vector ar , the vector ˆ | a| a =a r r gives the unit vector in the direction of ar � The position vector of a point R dividing a line segment joining the points P and Q whose position vectors are aand rb r respectively, in the ratio m : n (i) internally, is given by na mmb +n + r r
1
5582-5585
� The multiplication of a given vector by a scalar λ, changes the magnitude of the vector by the multiple |λ|, and keeps the direction same (or makes it opposite) according as the value of λ is positive (or negative) � For a given vector ar , the vector ˆ | a| a =a r r gives the unit vector in the direction of ar � The position vector of a point R dividing a line segment joining the points P and Q whose position vectors are aand rb r respectively, in the ratio m : n (i) internally, is given by na mmb +n + r r (ii) externally, is given by mb na m −n − r r
1
5583-5586
� For a given vector ar , the vector ˆ | a| a =a r r gives the unit vector in the direction of ar � The position vector of a point R dividing a line segment joining the points P and Q whose position vectors are aand rb r respectively, in the ratio m : n (i) internally, is given by na mmb +n + r r (ii) externally, is given by mb na m −n − r r � The scalar product of two given vectors aand rb r having angle θ between them is defined as | || | cos a b a b ⋅ = θ r r r r
1
5584-5587
� The position vector of a point R dividing a line segment joining the points P and Q whose position vectors are aand rb r respectively, in the ratio m : n (i) internally, is given by na mmb +n + r r (ii) externally, is given by mb na m −n − r r � The scalar product of two given vectors aand rb r having angle θ between them is defined as | || | cos a b a b ⋅ = θ r r r r Also, when a b ⋅ rr is given, the angle ‘θ’ between the vectors aand rb r may be determined by cosθ = | || a b| a b ⋅ rr r r � If θ is the angle between two vectors aand rb r , then their cross product is given as a b × r r = ˆ | || a b|sin n θ r r where ˆn is a unit vector perpendicular to the plane containing aand rb r
1
5585-5588
(ii) externally, is given by mb na m −n − r r � The scalar product of two given vectors aand rb r having angle θ between them is defined as | || | cos a b a b ⋅ = θ r r r r Also, when a b ⋅ rr is given, the angle ‘θ’ between the vectors aand rb r may be determined by cosθ = | || a b| a b ⋅ rr r r � If θ is the angle between two vectors aand rb r , then their cross product is given as a b × r r = ˆ | || a b|sin n θ r r where ˆn is a unit vector perpendicular to the plane containing aand rb r Such that ˆ , , r ra b n form right handed system of coordinate axes
1
5586-5589
� The scalar product of two given vectors aand rb r having angle θ between them is defined as | || | cos a b a b ⋅ = θ r r r r Also, when a b ⋅ rr is given, the angle ‘θ’ between the vectors aand rb r may be determined by cosθ = | || a b| a b ⋅ rr r r � If θ is the angle between two vectors aand rb r , then their cross product is given as a b × r r = ˆ | || a b|sin n θ r r where ˆn is a unit vector perpendicular to the plane containing aand rb r Such that ˆ , , r ra b n form right handed system of coordinate axes � If we have two vectors aand rb r , given in component form as 1 2 3 ˆ ˆ ˆ a a i a j a k = + + r and 1 2 3 ˆ ˆ ˆ b b i b j b k = + + r and λ any scalar, © NCERT not to be republished VECTOR ALGEBRA 461 then a b + r r = 1 1 2 2 3 3 ˆ ˆ ˆ ( ) ( ) ( ) a b i a b j a b k + + + + + ; a λr = 1 2 3 ˆ ˆ ˆ ( ) ( ) ( ) a i a j a k λ + λ + λ ; rr
1
5587-5590
Also, when a b ⋅ rr is given, the angle ‘θ’ between the vectors aand rb r may be determined by cosθ = | || a b| a b ⋅ rr r r � If θ is the angle between two vectors aand rb r , then their cross product is given as a b × r r = ˆ | || a b|sin n θ r r where ˆn is a unit vector perpendicular to the plane containing aand rb r Such that ˆ , , r ra b n form right handed system of coordinate axes � If we have two vectors aand rb r , given in component form as 1 2 3 ˆ ˆ ˆ a a i a j a k = + + r and 1 2 3 ˆ ˆ ˆ b b i b j b k = + + r and λ any scalar, © NCERT not to be republished VECTOR ALGEBRA 461 then a b + r r = 1 1 2 2 3 3 ˆ ˆ ˆ ( ) ( ) ( ) a b i a b j a b k + + + + + ; a λr = 1 2 3 ˆ ˆ ˆ ( ) ( ) ( ) a i a j a k λ + λ + λ ; rr a b = 1 1 2 2 3 3 a b a b a b + + ; and a b × r r = 1 1 1 2 2 2 ˆ ˆ ˆ
1
5588-5591
Such that ˆ , , r ra b n form right handed system of coordinate axes � If we have two vectors aand rb r , given in component form as 1 2 3 ˆ ˆ ˆ a a i a j a k = + + r and 1 2 3 ˆ ˆ ˆ b b i b j b k = + + r and λ any scalar, © NCERT not to be republished VECTOR ALGEBRA 461 then a b + r r = 1 1 2 2 3 3 ˆ ˆ ˆ ( ) ( ) ( ) a b i a b j a b k + + + + + ; a λr = 1 2 3 ˆ ˆ ˆ ( ) ( ) ( ) a i a j a k λ + λ + λ ; rr a b = 1 1 2 2 3 3 a b a b a b + + ; and a b × r r = 1 1 1 2 2 2 ˆ ˆ ˆ i j k a b c a b c Historical Note The word vector has been derived from a Latin word vectus, which means “to carry”
1
5589-5592
� If we have two vectors aand rb r , given in component form as 1 2 3 ˆ ˆ ˆ a a i a j a k = + + r and 1 2 3 ˆ ˆ ˆ b b i b j b k = + + r and λ any scalar, © NCERT not to be republished VECTOR ALGEBRA 461 then a b + r r = 1 1 2 2 3 3 ˆ ˆ ˆ ( ) ( ) ( ) a b i a b j a b k + + + + + ; a λr = 1 2 3 ˆ ˆ ˆ ( ) ( ) ( ) a i a j a k λ + λ + λ ; rr a b = 1 1 2 2 3 3 a b a b a b + + ; and a b × r r = 1 1 1 2 2 2 ˆ ˆ ˆ i j k a b c a b c Historical Note The word vector has been derived from a Latin word vectus, which means “to carry” The germinal ideas of modern vector theory date from around 1800 when Caspar Wessel (1745-1818) and Jean Robert Argand (1768-1822) described that how a complex number a + ib could be given a geometric interpretation with the help of a directed line segment in a coordinate plane
1
5590-5593
a b = 1 1 2 2 3 3 a b a b a b + + ; and a b × r r = 1 1 1 2 2 2 ˆ ˆ ˆ i j k a b c a b c Historical Note The word vector has been derived from a Latin word vectus, which means “to carry” The germinal ideas of modern vector theory date from around 1800 when Caspar Wessel (1745-1818) and Jean Robert Argand (1768-1822) described that how a complex number a + ib could be given a geometric interpretation with the help of a directed line segment in a coordinate plane William Rowen Hamilton (1805-1865) an Irish mathematician was the first to use the term vector for a directed line segment in his book Lectures on Quaternions (1853)
1
5591-5594
i j k a b c a b c Historical Note The word vector has been derived from a Latin word vectus, which means “to carry” The germinal ideas of modern vector theory date from around 1800 when Caspar Wessel (1745-1818) and Jean Robert Argand (1768-1822) described that how a complex number a + ib could be given a geometric interpretation with the help of a directed line segment in a coordinate plane William Rowen Hamilton (1805-1865) an Irish mathematician was the first to use the term vector for a directed line segment in his book Lectures on Quaternions (1853) Hamilton’s method of quaternions (an ordered set of four real numbers given as: ˆ ˆ ˆ ˆ ˆ ˆ , , , a bi cj dk i j k + + + following certain algebraic rules) was a solution to the problem of multiplying vectors in three dimensional space
1
5592-5595
The germinal ideas of modern vector theory date from around 1800 when Caspar Wessel (1745-1818) and Jean Robert Argand (1768-1822) described that how a complex number a + ib could be given a geometric interpretation with the help of a directed line segment in a coordinate plane William Rowen Hamilton (1805-1865) an Irish mathematician was the first to use the term vector for a directed line segment in his book Lectures on Quaternions (1853) Hamilton’s method of quaternions (an ordered set of four real numbers given as: ˆ ˆ ˆ ˆ ˆ ˆ , , , a bi cj dk i j k + + + following certain algebraic rules) was a solution to the problem of multiplying vectors in three dimensional space Though, we must mention here that in practice, the idea of vector concept and their addition was known much earlier ever since the time of Aristotle (384-322 B
1
5593-5596
William Rowen Hamilton (1805-1865) an Irish mathematician was the first to use the term vector for a directed line segment in his book Lectures on Quaternions (1853) Hamilton’s method of quaternions (an ordered set of four real numbers given as: ˆ ˆ ˆ ˆ ˆ ˆ , , , a bi cj dk i j k + + + following certain algebraic rules) was a solution to the problem of multiplying vectors in three dimensional space Though, we must mention here that in practice, the idea of vector concept and their addition was known much earlier ever since the time of Aristotle (384-322 B C
1
5594-5597
Hamilton’s method of quaternions (an ordered set of four real numbers given as: ˆ ˆ ˆ ˆ ˆ ˆ , , , a bi cj dk i j k + + + following certain algebraic rules) was a solution to the problem of multiplying vectors in three dimensional space Though, we must mention here that in practice, the idea of vector concept and their addition was known much earlier ever since the time of Aristotle (384-322 B C ), a Greek philosopher, and pupil of Plato (427-348 B
1
5595-5598
Though, we must mention here that in practice, the idea of vector concept and their addition was known much earlier ever since the time of Aristotle (384-322 B C ), a Greek philosopher, and pupil of Plato (427-348 B C
1
5596-5599
C ), a Greek philosopher, and pupil of Plato (427-348 B C )
1
5597-5600
), a Greek philosopher, and pupil of Plato (427-348 B C ) That time it was supposed to be known that the combined action of two or more forces could be seen by adding them according to parallelogram law
1
5598-5601
C ) That time it was supposed to be known that the combined action of two or more forces could be seen by adding them according to parallelogram law The correct law for the composition of forces, that forces add vectorially, had been discovered in the case of perpendicular forces by Stevin-Simon (1548-1620)
1
5599-5602
) That time it was supposed to be known that the combined action of two or more forces could be seen by adding them according to parallelogram law The correct law for the composition of forces, that forces add vectorially, had been discovered in the case of perpendicular forces by Stevin-Simon (1548-1620) In 1586 A
1
5600-5603
That time it was supposed to be known that the combined action of two or more forces could be seen by adding them according to parallelogram law The correct law for the composition of forces, that forces add vectorially, had been discovered in the case of perpendicular forces by Stevin-Simon (1548-1620) In 1586 A D
1
5601-5604
The correct law for the composition of forces, that forces add vectorially, had been discovered in the case of perpendicular forces by Stevin-Simon (1548-1620) In 1586 A D , he analysed the principle of geometric addition of forces in his treatise DeBeghinselen der Weeghconst (“Principles of the Art of Weighing”), which caused a major breakthrough in the development of mechanics
1
5602-5605
In 1586 A D , he analysed the principle of geometric addition of forces in his treatise DeBeghinselen der Weeghconst (“Principles of the Art of Weighing”), which caused a major breakthrough in the development of mechanics But it took another 200 years for the general concept of vectors to form
1
5603-5606
D , he analysed the principle of geometric addition of forces in his treatise DeBeghinselen der Weeghconst (“Principles of the Art of Weighing”), which caused a major breakthrough in the development of mechanics But it took another 200 years for the general concept of vectors to form In the 1880, Josaih Willard Gibbs (1839-1903), an American physicist and mathematician, and Oliver Heaviside (1850-1925), an English engineer, created what we now know as vector analysis, essentially by separating the real (scalar) © NCERT not to be republished MATHEMATICS 462 part of quaternion from its imaginary (vector) part
1
5604-5607
, he analysed the principle of geometric addition of forces in his treatise DeBeghinselen der Weeghconst (“Principles of the Art of Weighing”), which caused a major breakthrough in the development of mechanics But it took another 200 years for the general concept of vectors to form In the 1880, Josaih Willard Gibbs (1839-1903), an American physicist and mathematician, and Oliver Heaviside (1850-1925), an English engineer, created what we now know as vector analysis, essentially by separating the real (scalar) © NCERT not to be republished MATHEMATICS 462 part of quaternion from its imaginary (vector) part In 1881 and 1884, Gibbs printed a treatise entitled Element of Vector Analysis
1
5605-5608
But it took another 200 years for the general concept of vectors to form In the 1880, Josaih Willard Gibbs (1839-1903), an American physicist and mathematician, and Oliver Heaviside (1850-1925), an English engineer, created what we now know as vector analysis, essentially by separating the real (scalar) © NCERT not to be republished MATHEMATICS 462 part of quaternion from its imaginary (vector) part In 1881 and 1884, Gibbs printed a treatise entitled Element of Vector Analysis This book gave a systematic and concise account of vectors
1
5606-5609
In the 1880, Josaih Willard Gibbs (1839-1903), an American physicist and mathematician, and Oliver Heaviside (1850-1925), an English engineer, created what we now know as vector analysis, essentially by separating the real (scalar) © NCERT not to be republished MATHEMATICS 462 part of quaternion from its imaginary (vector) part In 1881 and 1884, Gibbs printed a treatise entitled Element of Vector Analysis This book gave a systematic and concise account of vectors However, much of the credit for demonstrating the applications of vectors is due to the D
1
5607-5610
In 1881 and 1884, Gibbs printed a treatise entitled Element of Vector Analysis This book gave a systematic and concise account of vectors However, much of the credit for demonstrating the applications of vectors is due to the D Heaviside and P
1
5608-5611
This book gave a systematic and concise account of vectors However, much of the credit for demonstrating the applications of vectors is due to the D Heaviside and P G
1
5609-5612
However, much of the credit for demonstrating the applications of vectors is due to the D Heaviside and P G Tait (1831-1901) who contributed significantly to this subject
1
5610-5613
Heaviside and P G Tait (1831-1901) who contributed significantly to this subject —� � � � �— © NCERT not to be republished THREE D IMENSIONAL G EOMETRY 463 � The moving power of mathematical invention is not reasoning but imagination
1
5611-5614
G Tait (1831-1901) who contributed significantly to this subject —� � � � �— © NCERT not to be republished THREE D IMENSIONAL G EOMETRY 463 � The moving power of mathematical invention is not reasoning but imagination – A
1
5612-5615
Tait (1831-1901) who contributed significantly to this subject —� � � � �— © NCERT not to be republished THREE D IMENSIONAL G EOMETRY 463 � The moving power of mathematical invention is not reasoning but imagination – A DEMORGAN � 11
1
5613-5616
—� � � � �— © NCERT not to be republished THREE D IMENSIONAL G EOMETRY 463 � The moving power of mathematical invention is not reasoning but imagination – A DEMORGAN � 11 1 Introduction In Class XI, while studying Analytical Geometry in two dimensions, and the introduction to three dimensional geometry, we confined to the Cartesian methods only
1
5614-5617
– A DEMORGAN � 11 1 Introduction In Class XI, while studying Analytical Geometry in two dimensions, and the introduction to three dimensional geometry, we confined to the Cartesian methods only In the previous chapter of this book, we have studied some basic concepts of vectors
1
5615-5618
DEMORGAN � 11 1 Introduction In Class XI, while studying Analytical Geometry in two dimensions, and the introduction to three dimensional geometry, we confined to the Cartesian methods only In the previous chapter of this book, we have studied some basic concepts of vectors We will now use vector algebra to three dimensional geometry
1
5616-5619
1 Introduction In Class XI, while studying Analytical Geometry in two dimensions, and the introduction to three dimensional geometry, we confined to the Cartesian methods only In the previous chapter of this book, we have studied some basic concepts of vectors We will now use vector algebra to three dimensional geometry The purpose of this approach to 3-dimensional geometry is that it makes the study simple and elegant*
1
5617-5620
In the previous chapter of this book, we have studied some basic concepts of vectors We will now use vector algebra to three dimensional geometry The purpose of this approach to 3-dimensional geometry is that it makes the study simple and elegant* In this chapter, we shall study the direction cosines and direction ratios of a line joining two points and also discuss about the equations of lines and planes in space under different conditions, angle between two lines, two planes, a line and a plane, shortest distance between two skew lines and distance of a point from a plane