Question

If $\cos A=\frac{\sqrt{3}}{2}$, find the value of $\sin 2A$

Answer 1

We know, $\sin 2A=2\sin A\cos A$

$\Rightarrow \sin 2A=2\sqrt{1-\frac{3}{4}}\times \frac{\sqrt{3}}{2}$

$=2\times \frac{1}{2}\times \frac{\sqrt{3}}{2}=\frac{\sqrt{3}}{2}$