A) \[2\hat{i}+\hat{j}-2\hat{k}\]
B) \[2(2\hat{i}-\hat{j}+2\hat{k})\]
C) \[3(2\hat{i}-\hat{j}-2\hat{k})\]
D) \[2(2\hat{i}+\hat{j}-2\hat{k})\]
E) \[2(2\hat{i}-\hat{j}-2\hat{k})\]
Correct Answer: E
Solution :
Required vector \[=\overrightarrow{a}\times \overrightarrow{b}=\left| \begin{matrix} {\hat{i}} & {\hat{j}} & {\hat{k}} \\ 2 & 2 & 1 \\ 1 & -2 & 2 \\ \end{matrix} \right|\] \[=\hat{i}(4+2)-\hat{j}(4-1)+\hat{k}(-4-2)\] \[=6\hat{i}-3\hat{j}-6\hat{k}\] \[=3(2\hat{i}-\hat{j}-2\hat{k})\] But its magnitude is not 6. Therefore correct answer is \[2(2\hat{i}-\hat{j}-2\hat{k})\]You need to login to perform this action.
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