How do I test if two vectors are coplanar?

[Philosophaie]

I have two vectors:

r1v=r1x*i + r1y*j + r1z*k
r2v=r2x*i + r2y*j + r2z*k

and

r1=Math.sqrt(r1x^2 + r1y^2 + r1z^2)
r2=Math.sqrt(r2x^2 + r2y^2 + r2z^2)

How do I find out if they are coplanar or not?

I know if they are perpendicular:

r1v cross r2v = 0

 

[MathematicalPhysicist]

You can use the next criterion:
http://mathworld.wolfram.com/Coplanar.html

Though I am not sure how you can find from your vectors the 4 points.

But obviously if the vectors don't coincide (i.e are actually the same vector) then they make up a plane, i.e coplanar.

 

[Muphrid]

Yeah, it's not really meaningful to ask if two vectors are or are not coplanar. You can ask if three vectors are coplanar, however.