Question

If $\overline{a}=\overline{i}+\overline{j}+\overline{k},\overline{b}=2\overline{i}-3\overline{j}+\overline{k}$, then $\overline{a}\times \overline{b}$ is

• A. $4\overline{i}+\overline{j}-5\overline{k}$
• B. $4\overline{i}-\overline{j}+5\overline{k}$
• C. $4\overline{i}+\overline{j}+5\overline{k}$
• D. $4\overline{i}-\overline{j}-5\overline{k}$

Answer 1

The correct option is A $4\overline{i}+\overline{j}-5\overline{k}$

$\overrightarrow{a}\times \overrightarrow{b}=\left|\begin{array}{ccc}\hat{i}& \hat{j}& \hat{k}\\ 1& 1& 1\\ 2& -3& 1\end{array}\right|=4\hat{i}+\hat{j}-5\hat{k}$