# What is Cos (inverse) 1/2 ?

${\cos}^{-} 1 \left(\frac{1}{2}\right) = \frac{\pi}{3}$
${\cos}^{-} 1 \left(\frac{1}{2}\right)$ means an angle measure whose cosine is $\frac{1}{2}$. Such an angle is $\frac{\pi}{3}$