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Q1   Find |\vec a \times \vec b |, if \vec a = \hat i - 7 \hat j + 7 \hat k \: \: and \: \: \vec b = 3 \hat i - 2 \hat j + 2 \hat k

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Given in the question,

\\ \vec a = \hat i - 7 \hat j + 7 \hat k \: \: and \: \: \\\vec b = 3 \hat i - 2 \hat j + 2 \hat k

and we need to find |\vec a \times \vec b |

Now,

|\vec a \times \vec b | =\begin{vmatrix} \hat i &\hat j &\hat k \\ 1 &-7 &7 \\ 3& -2 &2 \end{vmatrix}

|\vec a \times \vec b | =\hat i(-14+14)-\hat j(2-21)+\hat k(-2+21)

|\vec a \times \vec b | =19\hat j+19\hat k

So the value of |\vec a \times \vec b | is 19\hat j+19\hat k

Posted by

Pankaj Sanodiya

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