A) \[10\sqrt{3}\]
B) \[5\sqrt{3}\]
C) 8
D) 4
Correct Answer: B
Solution :
\[\Delta =\frac{1}{2}|\mathbf{a}\times \mathbf{b}|\] But \[\mathbf{a}\times \mathbf{b}=\left| \begin{matrix} \mathbf{i} & \mathbf{j} & \mathbf{k} \\ 3 & 1 & -2 \\ 1 & -3 & 4 \\ \end{matrix} \right|=-2\mathbf{i}-14\mathbf{j}-10\mathbf{k}.\] Hence \[\Delta =\frac{1}{2}|\mathbf{a}\times \mathbf{b}|=\frac{1}{2}\sqrt{4+196+100}=5\sqrt{3}.\]
You need to login to perform this action.
You will be redirected in
3 sec
