a . i^i^ + a . j^j^ + a . k^k^ is equal to
a
2a
3a
0
If a = 3, b = 4, then a value of λ for which a + λb is perpendicular to a - λb is
916
34
32
43
The projection of a = 2i^ + 3j^ - 2k^ on b = i^ + 2j^ + 3k^ is
114
214
14
- 214
If the vectors 4i^ + 11j^ + mk^, 7i^ + 2j^ + 6k^ and i^ + 5j^ + 4k^ are coplanar, then m is equal to
38
- 10
10
If a × b = 4 and a . b = 2, then a2b2 is equal to
6
2
20
8
The angle between the vectors a + b and a - b when a = (1, 1, 4) and b = (1, - 1, 4) is
45°
90°
15°
30°
If a, b, c are mutually perpendicular unit vectors, then a + b + c is equal to
3
1
If ABCDEF is a regular hexagon, then AD + EB + FC equals
2 AB
4 AB
3 AB
The projection of the vector 2i^ + j^ - 3k^ on the vector i^ - 2j^ + k^ is
- 314
314
- 32
An unit vector perpendicular to the plane containing the vectors i^ - j^ + k^ and - i^ + j^ + k^ is
± i^ - j^2
i^ + k^2
± j^ - k^2
∓ i^ + j^2
D.
Let a = i^ - j^ + k^ and b = - i^ + j^ + k^And unit vector perpendicular to the plane a and b = ± a × ba × bNow, a × b = i^j^k^1- 11- 111 = i^- 1 - 1 - j^1 + 1 + k^1 - 1 = - 2i^ - 2j^ a × b = 22 + 22 = 22∴ a × ba × b = ∓ 2i^ + j^22 = ∓ i^ + j^2