Answer
$-\dfrac{\pi}{3}$
Work Step by Step
Suppose $\theta = \sin^{-1} (-\dfrac{\sqrt 3}{2})$
This gives: $\sin \theta= -\dfrac{\sqrt 3}{2}$
Now, $\theta = \sin^{-1} (-\dfrac{\sqrt 3}{2})=-\dfrac{\pi}{3}$
Therefore, $\sin^{-1} (-\dfrac{\sqrt 3}{2})=-\dfrac{\pi}{3}$
