# How do you solve and find the value of cos(arccos(-1/2))?

Dec 2, 2016

$- \frac{1}{2}$
$\cos x = - \frac{1}{2}$ --> 2 solution arcs -->
arc $x = \frac{2 \pi}{3}$ and arc $x = \frac{4 \pi}{3}$
$\cos \left(\frac{2 \pi}{3}\right) = \cos \left(\frac{4 \pi}{3}\right) = - \frac{1}{2}$