The direction cosines of a vector `hati+hatj+sqrt(2) hatk` are:-

Options

A. `(1)/(2),(1)/(2),1`
B. `(1)/sqrt(2),(1)/sqrt(2),(1)'(2)`
C. `(1)/(2),(1)/(2),(1)sqrt(2)`
D. `(1)/sqrt(2),(1)/sqrt(2),(1)/sqrt(2)`

Answer

C

Explanation

`vecA=hati+hatj+sqrt(2)hatk`
`cos alpha=(Ax)/(A),cos beta=(Ay)/(A), cosgamma=(Az)/(A)`
`cos alpha=(1)/(2), cos beta=(1)/(2), cos gamma=sqrt(2)/(2)=(1)/sqrt(2)`