so, i'm trying to determine if the vectors(adsbygoogle = window.adsbygoogle || []).push({});

2,1,-1

1,1,0

2,-1,3

are coplanar. i take the triple product, finding the determinant of the matrix. it seems to be non-zero, but the answer key insists these are coplanar. am i wrong, or perhaps the book? any input would be appreciated!

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# Homework Help: Vector algebra

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