Question

The angle which the vector `vec(A)=2hat(i)+3hat(j)` makes with the y-axis, where `hat(i)` and `hat(j)` are unit vectors along x- and y-axis, respectively, is
A. `cos^(-1)(3//5)`
B. `cos^(-1)(2//3)`
C. `tan^(-1)(2//3)
D. `sin^(-1)(2//3)`

Answer 1

Correct Answer - C
See (figure)
`tan beta=2/3` or `beta=tan^(-1)(2/3)`