Answer
$1$
Work Step by Step
Convert the angle measure to degrees to obtain:
$=\frac{\pi}{4} \cdot \frac{180^o}{\pi} = 45^o$
Thus,
$\tan{\frac{\pi}{4}}
\\= \tan{45^o}$
From Section 2.1 (page 50) , we learned that:
$\tan{45^o}=1$