Answer
$\tan^{-1}(\tan(\frac{\pi}{4})) = \frac{\pi}{4}$
Work Step by Step
Note that $\tan^{-1}(\tan(x)) = x$, essentially the inverse tangent and tangent functions negate each other. Applying this, $\tan^{-1}(\tan(\frac{\pi}{4})) = \frac{\pi}{4}$.
