Let the pair of vector `veca,vecb` and `vecc,vecd` each determine a plane. Then the planes are parallel if

Options

A. `(vecaxxvecc)xx(vecbxxvecd)=vec0`
B. `(vecaxxvecc).(vecbxxvecd)=vec0`
C. `(vecaxxvecb)xx(veccxxvecd)=vec0`
D. `(vecaxxvecb).(veccxxvecd)=vec0`

Answer

c

Explanation

`veca xx vecb` is a vector perpendicular to the plane containing `veca and vecb` similarly, `vecc xx vecd` is a vector perpendicular to the plane containing , `vecc and vecd` thus , the two planes will be parallel if their normal i.e., `veca xx vecb and vecc xx vecd` are parallel. thus
`(veca xx vecb) xx (vecc xx vecd)) = vec0`