## Precalculus (10th Edition)

$-\frac{\pi}{2}\lt x\lt\frac{\pi}{2}.$
$\tan^{-1}(\tan(x))=x$ where $-\frac{\pi}{2}\lt x\lt\frac{\pi}{2}.$ (as this is the range of $f(x)=\tan^{-1}(x).$)