# How do you evaluate cos^-1(cos((pi)/6))?

$\frac{\pi}{6}$
${\cos}^{-} 1 \left(\cos \theta\right) = \theta$
(Since ${\cos}^{-} 1$ is the inverse function of $\cos$)
Hence: ${\cos}^{-} 1 \left(\cos \left(\frac{\pi}{6}\right)\right) = \frac{\pi}{6}$