Question

The angle between the vectors 2î+ 3j + k and 2i - 3j - k is

a)π/4
b)π/3
c)π/2
d) None​

Answer 1

d

Explanation:

let vector A=2i+3j+k and vector B=2i-3j-k

so

vec A. vec B=ABcos¤

(2i+3j+k)(2i-3j-k)=(4+9+1)^1/2 ×(4+9+1)^1/2 ×cos¤

4-9-1=14 cos¤

-6/14=cos¤

¤=cos^-1(-3/7)

Answer 2

The angle between the given vectors is 115.37°.

So the answer is d) None.

It is solved in the given picture.