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