Answer
$-\frac{\sqrt 3}{3}$
Work Step by Step
The given problem can be solved as:
$cot({sin^{-1}(-\frac{\sqrt 3}{2})})=cot ( -\frac{\pi}{3})$
or, $cot ( -\frac{\pi}{3})=\frac{-\sqrt 3}{3}$
Hence. the final answer is: $-\frac{\sqrt 3}{3}$