Answer: b x d = 0.
- A b x d = 0
- B b.d = 0
- C (c-a).(b x d) = 0
- D (c-a) x b = 0
Correct answer: A. b x d = 0
Explanation: Two lines r = a + lambda*b and r = c + mu*d are coplanar if and only if (c-a).(b x d) = 0.
Three mutually perpendicular axes x, y, z meeting at the origin O, with a point P located by its (x, y, z) coordinates.
Concept context
Lines and planes in 3D space, direction cosines, distances, and angles