The angles which the vector `A=3hati + 6hatj+2hatk` makes with the co-ordinate axes are

Options

A. `"cos"^(-1) 3/7, "cos"^(-1)4/7, "cos"^(-1) 1/7`
B. `"cos"^(-1)3/7, "cos"^(-1)6/7, "cos"^(-1) 2/7`
C. `"cos"^(-1) 4/7, "cos"^(-1)5/7, "cos"^(-1) 3/7`
D. None of these

Answer

B

Explanation

`hatA=(3hati+ b hatj + 2hatk)/sqrt(9+36+4) =(3/7 hati+6/7hatj+2/7hatk)`. If `alpha, beta` and `gamma` are angles made by `vecA` with coordinate axes, then cos `alpha=3/7 , cos beta=6/7` and `cos gamma=2/7`.