A) \[\frac{5\pi }{6}\]
B) \[\frac{3\pi }{4}\]
C) \[\frac{\pi }{2}\]
D) \[\frac{2\pi }{3}\]
Correct Answer: A
Solution :
\[\left( \vec{a}.\vec{c}-\frac{\sqrt{3}}{2} \right)\vec{b}-\left( \vec{a}.\vec{b}+\frac{\sqrt{3}}{2} \right)\vec{c}=0\] \[\Rightarrow \]\[\vec{a}.\vec{b}=\cos \theta =-\sqrt{3}/2\Rightarrow \theta =5\pi /6\]You need to login to perform this action.
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