Question

If 1st vector: A
2nd vector: B
their Resltunt is R
Now, Twice of A vector gives you twice of resultant.

Question: Find the angle of the vectors A,B

Answer 1

Explanation:

here, .....

B+A=R

SO....

|a+b|^2=a^2+b^2+2ab cos theta......1

acc, to given problem ......

2× |a+b|^2=(2a)^2+b^2+2×2ab cos theta......2

on subtracting 2-1,,,,,

|a+b|^2=3a^2+2ab cos theta

r^2=3a^2+2ab cos theta

theta=cos ^-1{(r^2-3a^2)/2ab}