Question

Which of the following operation will give a vector that is perpendicular to both vectors a and b?

(a) a x b

(b) a.b

(c) b x a

(d) both a x b and b x a

I have been asked this question in an international level competition.

My query is from Computational Geometry in portion Computational Geometry of Data Structures & Algorithms II

Answer 1

Right choice is (d) both a x b and b x a

Best explanation: The resultant vector from the cross product of two vectors is perpendicular to the plane containing both vectors. So both a x b and b x a will give a vector that is perpendicular to both vectors a and b.