## Calculus (3rd Edition)

(A) $0\leq r\leq 3$ and $-\pi \leq \theta\leq 0$. (B) $0\leq r\leq 3$ and $\pi/4 \leq \theta\leq \pi/2$. (C) $3\leq r\leq 5$ and $3\pi/4 \leq \theta\leq \pi$.
We see that the inner radius is $r=3$ and the outer radius is $r=5$. Thus we have: (A) $0\leq r\leq 3$ and $-\pi \leq \theta\leq 0$. (B) $0\leq r\leq 3$ and $\pi/4 \leq \theta\leq \pi/2$. (C) $3\leq r\leq 5$ and $3\pi/4 \leq \theta\leq \pi$.