Answer
$\pm\frac{\pi}{3}, \frac{5\pi}{3}, \frac{7\pi}{3} $
Work Step by Step
Let $cos(x)=\frac{1}{2}$, we can find general forms of the solutions as $x=2k\pi\pm\frac{\pi}{3}$ where $k$ is an integer. For $k=0,1$, we have $x=\pm\frac{\pi}{3}, \frac{5\pi}{3}, \frac{7\pi}{3} $
