The angle subtended by vector `vecA = 4 hati + 3hatj + 12hatk` with the x-axis is :

Options

A. `sin ^(-1)((3)/(13))`
B. `sin ^(-1)((4)/(13))`
C. `cos ^(-1)((4)/(13))`
D. `cos ^(-1)((3)/(13))`

Answer

C

Explanation

`cos theta = (vecA.hati)/(|vecA||hati|)=(4 hati + 3hatj+ 12 hatk)/(sqrt(4^(2) +3^(2) + 12^(2) xx 1))=(4)/(13)`
`theta = cos ^(-1)((4)/(13))`