y
x
(−1, 0)
(0, -1)
(1, 0)
(0, 1)
(cos, sin)
( , )
( , )
( , )
(− , )
2
2
√
2
2
√
2
1
(− , − )
( , − )
(− , )
2
1
(− , − )
2
1
( , − )
2
1
( , − )
2
1
(− , − )
2
1
2
1
(− , )
2
1
3
2
√
3
2
√
3
2
√
3
2
√
3
2
√
3
2
√
3
2
√
3
2
√
2
2
√
2
2
√
2
2
√
2
2
√
2
2
√
2
2
√
2
2
√
0
π/6
π/4
π/3
π/2
2π/3
3π/4
5π/6
π
7π/6
5π/4
4π/3
3π/2
5π/3
7π/4
11π/6