Question: Evaluate $\cos \left\{\cos ^{-1}\left(\frac{-\sqrt{3}}{2}\right)+\frac{\pi}{6}\right\}$
Solution:
$\cos \left\{\pi-\frac{\pi}{6}+\frac{\pi}{6}\right\}$ [Refer to question 2(ii)]
$=\cos \{\pi\}$
$=\cos \left(\frac{\pi}{2}+\frac{\pi}{2}\right)$
$=-1$
