Answer
(a) $\sin{(-\frac{3\pi}{2})}=1$
(b) $\cos{(-\frac{3\pi}{2})}=0$
(c) $\tan{(-\frac{3\pi}{2})} \text{ is undefined}$
Work Step by Step
RECALL:
$\sin{s} = y
\\\cos{s} = x
\\\tan{s} = \frac{y}{x}$
The angle $-\dfrac{3\pi}{2}$ ($\frac{3\pi}{2}$ degrees clockwise) will intersect the unit circle at the point $(0, 1)$ (refer to Figure 15 on page 113).
The point $(0, 1)$ has:
$x=0
\\y=1$
Thus,
$\sin{(-\frac{3\pi}{2})}=1
\\\cos{(-\frac{3\pi}{2})}=0
\\\tan{(-\frac{3\pi}{2})}=\frac{1}{0} \text{ (undefined)}$
