Question

If vector A x vector B = vector B x vector A ,then the angle between A and B is 

(a)  π 

(b)  π/3 

(c)  π/2 

(d)  π/4.

Answer 1

Answer is (a) π 

\(\vec{A}\times\vec{B}\) = AB sinθ \(\hat{n}\)

\(\vec{B}\times\vec{A}\) = AB sin(2π - θ)\(\hat{n}\)

AB sinθ \(\hat{n}\) = AB sin(2π - θ)\(\hat{n}\)

θ = 2π - θ

2θ = 2π

θ = π 

Answer 2

The correct answer is: