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Evaluate $n = <4, 1, -2> \times <0, 1, 2>$

Using the matrix method I got:

$n = \begin{vmatrix}i&j&k\\4&1&-2\\0&1&2\end{vmatrix} $

But this gives me $<4, 8, 4>$ instead of $<4, -8, 4>$ using the cofactor evaluation method?

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    I might ask how you got $4$ instead of $0$ for the first coordinate when using the above matrix. – 2017-01-16

1 Answers 1

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You've input the third row as $(0,1,-2)$, when it should be $(0,1,2)$.