Question

Find a unit vector in xy-plane that makes an angle of 45° with the vector i + j and an angle of 60° with the vector 3i – 4 j.

Answer 1

Let the vector be r = xi + yj.

We have to find r = r/|r| 

Let a = i + j and b = 3i – 4j

Now,

From Eqs. (i) and (ii), we get 

x = 13y

Thus,