Answer
1. $(1,0), sint=0, cost=1$,
2. $(\frac{\sqrt 2}{2},\frac{\sqrt 2}{2}), sint=\frac{\sqrt 2}{2}, cost=\frac{\sqrt 2}{2}$,
3. $(0,1), sint=1, cost=0$,
4. $(-\frac{\sqrt 2}{2},\frac{\sqrt 2}{2}), sint=\frac{\sqrt 2}{2}, cost=-\frac{\sqrt 2}{2}$,
5. $(-1,0), sint=0, cost=-1$,
6. $(-\frac{\sqrt 2}{2},-\frac{\sqrt 2}{2}), sint=-\frac{\sqrt 2}{2}, cost=-\frac{\sqrt 2}{2}$,
7. $(0,-1), sint=-1, cost=0$,
8. $(\frac{\sqrt 2}{2},-\frac{\sqrt 2}{2}), sint=-\frac{\sqrt 2}{2}, cost=\frac{\sqrt 2}{2}$,
Work Step by Step
Start from $(1,0)$ and go counter clockwise, there are 8 points on unit circle,
and their $(x,y)$ values, $sint=y, cost=x$ can be found as the following:
1. $(1,0), sint=0, cost=1$,
2. $(\frac{\sqrt 2}{2},\frac{\sqrt 2}{2}), sint=\frac{\sqrt 2}{2}, cost=\frac{\sqrt 2}{2}$,
3. $(0,1), sint=1, cost=0$,
4. $(-\frac{\sqrt 2}{2},\frac{\sqrt 2}{2}), sint=\frac{\sqrt 2}{2}, cost=-\frac{\sqrt 2}{2}$,
5. $(-1,0), sint=0, cost=-1$,
6. $(-\frac{\sqrt 2}{2},-\frac{\sqrt 2}{2}), sint=-\frac{\sqrt 2}{2}, cost=-\frac{\sqrt 2}{2}$,
7. $(0,-1), sint=-1, cost=0$,
8. $(\frac{\sqrt 2}{2},-\frac{\sqrt 2}{2}), sint=-\frac{\sqrt 2}{2}, cost=\frac{\sqrt 2}{2}$,
