#### Answer

-$\frac{\pi}{4}\leq \Theta \leq \frac{3\pi}{4} $ ,$0\leq r \leq cos\Theta$

#### Work Step by Step

Describing the given region in polar coordinates of the below graph
y=x=>$\Theta=\frac{\pi}{4},y=-x=>\Theta$
$=\frac{3\pi}{4}.y=1=>cos \Theta$
-$\frac{\pi}{4}\leq \Theta \leq \frac{3\pi}{4} $ ,$0\leq r \leq cos\Theta$