Answer
(a) $\frac{\sqrt 2}{2}$
(a) $-\frac{\sqrt 2}{2}$
Work Step by Step
1. Find the reference number for t = $3\pi/4$
$$t^- = \pi - \frac{3\pi}{4} = \frac{\pi}{4}$$
2. Use table 1 (page 404), we can see that the terminal point for that reference number is: $(\frac{\sqrt 2 }{2}, \frac{\sqrt 2}{2})$
3. Since $3\pi/4$ is in Quadrant II, x is negative and y is positive:
Terminal point = $(-\frac{\sqrt 2 }{2}, \frac{\sqrt 2}{2})$
$sin \space t = y = \sqrt 2/2$ and
$cos \space t = x = -\sqrt 2/2$
