A) \[{{30}^{o}}\]
B) \[{{60}^{o}}\]
C) \[{{90}^{o}}\]
D) x
Correct Answer: C
Solution :
We have \[\mathbf{a}+\mathbf{b}=4\mathbf{i}+\mathbf{j}-\mathbf{k}\] and \[\mathbf{a}-\mathbf{b}=-2\mathbf{i}+3\mathbf{j}-5\mathbf{k}.\] Clearly \[(\mathbf{a}+\mathbf{b})\,.\,(\mathbf{a}-\mathbf{b})=0.\] Hence \[(\mathbf{a}+\mathbf{b})\,\bot \,(\mathbf{a}-\mathbf{b}).\]You need to login to perform this action.
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