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QUESTION

Evaluate $\textbf{a}\times\textbf{b}$ where
$\textbf{a}=\textbf{i}-2\textbf{j}+2\textbf{k}$ and
$\textbf{b}=\textbf{i}+\textbf{j}-2\textbf{k}$.

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ANSWER

$\textbf{a}\times\textbf{b}= \left|\begin{array}{ccc}
\textbf{i}&\textbf{j}&\textbf{k}\\1&-2&2\\1&1&-2
\end{array}\right |=(4-2,2-(-2),1-(-2))
=2\textbf{i}+4\textbf{j}+3\textbf{k}$




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