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

Options

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

Answer

A

Explanation

`A = |A| = sqrt((3)^2 +(6)^2 +(2))^2`
=7
`alpha = cos^(-1) ((A_x)/(A)) = cos ^(-1) ((3)/(7))`
= angle of A with positivej x-axis.
Similarly, `beta and lambda` angles.