Correct Answer – B
If `vec (r ) = x hat(i) + y hat(j) + z hat(k) , r = sqrt(x^(2) + y^(2) + z^(2))`
`alpha , beta , gamma` : angles made by `vec(r )` with coordinates axes
`cos alpha = (x)/( r) , cos beta = (y) /( r ) , cos gamma = (z)/( r )`
Direction cosines ,` cos alpha , cos beta , cos gamma`
`vec(A) = 3 i + 6 j – 2k , |vec(A)|= A = sqrt((3)^(2) + (6)^(2) + (-2)^(2)) = 7`
`cos alpha = (3)/(7) , cos beta = (6)/(7) , cos gamma = (-2)/(7)`