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 the above

Answer

A

Explanation

(a) Vector`A=sqrt((3)^(2)+(6)^(2)+(2)^(2))=7`
`alpha=cos^(-1)((3)/(7)),beta=cos^(-1)((6)/(7)),gamma=cos^(-1)((2)/(i))`