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# Show that three vectors are coplanar. Watch

1. Show that the vectors a,b and c are coplanar if and only if a.bxc=0.

I know this is a really easy question, I just don't see how I could show this .
2. a.bxc would represent the volume of the solid with vector sides a, b, c.
If this volume is zero, then all three vectors must lie in the same plane.
How are you expecting/expected to 'show' this ?
3. (Original post by Bric)
a.bxc would represent the volume of the solid with vector sides a, b, c.
If this volume is zero, then all three vectors must lie in the same plane.
How are you expecting/expected to 'show' this ?
Well, since it's an iff you'd do the obvious direction that them being coplanar implies the volume is 0, but also that the volume being 0 implies they are coplanar.

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Updated: April 8, 2013
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