Question

If a vector $\overrightarrow{P}$ making angles $\alpha ,\beta$ and $\gamma$ respectively with the X, Y and Z axes respectively.Then $si{n}^2\alpha +si{n}^2\beta +si{n}^2\gamma =$

• A. 0
• B. 1
• C. 2
• D. 3

Answer 1

The correct option is C

2

$si{n}^2\alpha +si{n}^2\beta +si{n}^2\gamma =1-co{s}^2\alpha +1-co{s}^2\beta +1-co{s}^2\gamma =3-(co{s}^2\alpha +co{s}^2\beta +co{s}^2\gamma )=3-1=2$