what is a coplanar vector

Dear Sujit,

First of all the word coplanar refers to two or more vectors. It is a relative term which is used to state the position of a vector with respect to other(s) vector(s) for reference to a problem or statement. If two or more vectors are in the same plane or in other words if all of the vectors share the same plane then they are refered to as coplanar vectors.

Vectors which lies on same plane are known as coplanar vector.

Three Vectors a, b, c are said to be co- planar vectors if they all lie in the same plane.. in case of coplanar vectors;

(axb).c = 0,, as (axb) gives a vector which is perpendicular to c, and dot product of two perpendicular vectors is 0.  This condition of coplanarity can be used to check whether the given vectors are coplanar or not.

very simply, coplaner vectors are any vectors that all reside in the same plane.