动画282：圆与角度的交互演示

GeoGebra 命令及参数

1. Circle(A, B) → c
2. Segment(A, B) → f
3. PointIn(b) → C
4. Distance(C, c) → d
5. Circle(C, d) → e
6. Intersect(e, c) → D, , ,
7. Point(c) → E
8. Tangent(E, e) → g, h
9. Intersect(c, g, 2) → F
10. Intersect(e, g) → G
11. Ray(D, E) → i
12. Ray(D, F) → j
13. Ray(D, G) → k
14. Segment(D, F) → l
15. Segment(D, G) → m
16. Segment(D, E) → n
17. Min({l, m, n}) → o
18. Circle(D, (0.3 * o)) → p
19. Intersect(p, k, 1) → H
20. Intersect(p, i, 1) → I
21. CircleSector(D, I, H) → q
22. Angle(C, G, E) → α
23. Dilate(E, If[0 < r ≤ 1, 1 - r, 0], G) → E'
24. Segment(E, E') → s
25. Dilate(G, If[1 < r ≤ 2, 2 - r, 0], F) → G'
26. Segment(G, G') → t
27. Dilate(C, If[2 < r ≤ 3, 3 - r, 0], G) → C'
28. Segment(C, C') → f_1
29. Dilate(D, If[3 < r ≤ 4, 4 - r, 0], G) → D'
30. Dilate(D, If[3 < r ≤ 4, 4 - r, 0], E) → D'_1
31. Dilate(D, If[3 < r ≤ 4, 4 - r, 0], F) → D'_2
32. Segment(D, D'_1) → g_1
33. Segment(D, D') → h_1
34. Segment(D, D'_2) → i_1
35. Angle(E, D, G) → β
36. Rotate(I, If[4 < r ≤ 5, ((r - 4) * β), β], D) → I'
37. CircleSector(D, I, I') → c_1
38. Rotate(q, If[6 < r ≤ 7, ((r - 6) * β), β], D) → q'
39. Circle(A, B) → cc
40. Circle(C, D) → ee