Answer
$\displaystyle \frac{\pi}{8}$ , $\displaystyle \frac{5\pi}{6},\ \displaystyle \frac{5\pi}{4}$
Work Step by Step
If $ 0 \leq x < 2\pi$ then
$0 \displaystyle \leq \frac{x}{2} < \pi,$
and $x=2\displaystyle \cdot\frac{x}{2}$ so the corresponding values of x are
$2\displaystyle \cdot\frac{\pi}{16}=\frac{\pi}{8}$
$2\displaystyle \cdot\frac{5\pi}{12}=\frac{5\pi}{6}$
$2\displaystyle \cdot\frac{5\pi}{8}=\frac{5\pi}{4}$