Answer
$\frac{\pi}{4}$
Work Step by Step
RECALL:
Since $\tan{x}$ and $\tan^{-1}{x}$ are inverse functions of each other, then, for all valid values of $x$,
$\tan^{-1}{(\tan(x))}=x$
Thus,
$\tan^{-1}{(\tan{(\frac{\pi}{4})})}=\frac{\pi}{4}$
