单位圆中的三角函数：参考角与对称性演示

GeoGebra 命令及参数

1. Intersect(xAxis, yAxis) → A
2. Circle(A, 1) → c
3. Intersect(c, xAxis, 2) → B
4. Rotate(B, α, A) → B'
5. Angle(B, A, B') → β
6. Intersect(a, xAxis) → C
7. Polygon(A, C, B') → poly1, b', a_1, c_1
8. Angle(B', C, A) → γ
9. Rotate(B, π - α, A) → B'_1
10. Angle(B, A, B'_1) → δ
11. Rotate(B, π + α, A) → B'_2
12. Angle(B, A, B'_2) → ε
13. Rotate(B, (2 * π) - α, A) → B'_3
14. Angle(B, A, B'_3) → ζ
15. Segment(B'_1, B'_2) → d
16. Intersect(d, xAxis) → D
17. Polygon(B'_1, D, A) → poly2, a_2, b'_1, d_1
18. Polygon(D, B'_2, A) → poly3, a_3, d_2, b'_2
19. Polygon(A, C, B'_3) → poly4, b'_3, a_4, c_2