## Precalculus (6th Edition)

$\frac{3\pi}{4}$, $\frac{7\pi}{4}$
$2\cot x+1=-1$ $2\cot x=-2$ $\cot x=-1$ The only solutions in $[0, 2\pi)$ are $\frac{3\pi}{4}$ and $\frac{7\pi}{4}$.