## Precalculus (10th Edition)

$\tan^{-1} (1)=\frac{\pi}{4}$
Let $x$ =$\tan^{-1}(1)$ implies that: $x$ =$\tan^{-1}(1)$ implies that $\tan (x) =1$ Using exact values, $x=\frac{\pi}{4}$ Therefore: $\tan^{-1}(1)=\frac{\pi}{4}$