Answer
$\frac{\pi}{2}$
Work Step by Step
See figure. The enclosed area can be written as
$\int_{-\pi/4}^{\pi/4} (sec^2x-tan^2x) dx =\int_{-\pi/4}^{\pi/4} (1) dx=x|_{-\pi/4}^{\pi/4} =\frac{\pi}{4}-(-\frac{\pi}{4})=\frac{\pi}{2} $
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