# How do you evaluate cos(cos^-1(-sqrt3/2))?

$- \frac{\sqrt{3}}{2}$
Use $f {f}^{- 1} a = a$
Here, $f = \cos , {f}^{- 1} = {\cos}^{- 1} \mathmr{and} a = - \frac{\sqrt{3}}{2}$.