Answer
(a) See the graph
(b) Quadrant IV
(c) $\frac{7\pi}{4}$ and $-\frac{\pi}{4}$
Work Step by Step
(b)
A positive coterminal angle of $\frac{15\pi}{4}$ is $\frac{7\pi}{4}$
$\frac{3\pi}{2}\lt\frac{7\pi}{4}\lt2\pi$, therefore, it lies in quadrant IV.
(c)
$\frac{15\pi}{4}-2\pi=\frac{7\pi}{4}$
$\frac{15\pi}{4}-2(2\pi)=-\frac{\pi}{4}$
