动画演示三角形与圆锥曲线关系

GeoGebra 命令及参数

1. Rotate(A, 60°, B) → A'
2. Angle(A, B, A') → α
3. Ray(B, A) → f
4. Ray(B, A') → g
5. Point(f) → C
6. Point(g) → D
7. Polygon(C, D, B) → poly1, b, c, d
8. Rotate(D, 60°, B) → D'
9. Angle(D, B, D') → β
10. Rotate(C, (-(60°)), B) → C'
11. Angle(C', B, C) → γ
12. Line(C', D') → h
13. Segment(B, C) → i
14. Segment(B, D) → j
15. Min(i, j) → a
16. Segment(C, D) → k
17. Min(i, k) → l
18. Min(a, l) → m
19. Circle(B, (0.2 * m)) → e
20. Intersect(e, h, 1) → E
21. Intersect(e, i, 1) → F
22. Intersect(e, j, 1) → G
23. Intersect(e, h, 2) → H
24. Angle(D, C, B) → δ
25. Angle(B, D, C) → ε
26. Rotate(D, δ / 2, C) → D'_1
27. Angle(D, C, D'_1) → ζ
28. Ray(C, D'_1) → p
29. Rotate(B, ε / 2, D) → B'
30. Angle(B, D, B') → η
31. Ray(D, B') → q
32. Circle(C, (0.2 * m)) → r
33. Circle(D, (0.2 * m)) → s
34. Intersect(r, p, 1) → I
35. Intersect(r, k, 1) → J
36. Intersect(s, j, 1) → K
37. Intersect(s, q, 1) → L
38. Intersect(i, q) → M
39. Intersect(j, p) → N
40. CircleSector(B, E, F) → t
41. Rotate(t, If[0 < n ≤ 1, (n * π / 3), π / 3], B) → t'
42. Rotate(t', If[2 < n ≤ 3, ((n - 2) * π / 3), π / 3], B) → t''
43. Rotate(t'', If[4 < n ≤ 5, ((-(n - 4)) * π / 3), ((-π)) / 3], B) → t'''
44. Dilate(C, If[5 < n ≤ 6, 6 - n, 0], N) → C'_1
45. Segment(C, C'_1) → f_1
46. Dilate(D, If[6 < n ≤ 7, 7 - n, 0], M) → D'_2
47. Segment(D, D'_2) → g_1
48. Intersect(r, i, 1) → O
49. Intersect(s, k, 1) → P
50. CircleSector(C, I, O) → c_1
51. CircleSector(D, L, P) → d_1
52. Rotate(c_1, If[7 < n ≤ 8, ((-(n - 7)) * ζ), (-ζ)], C) → e_1
53. Rotate(d_1, If[8 < n ≤ 9, ((-(n - 8)) * η), (-η)], D) → h_1
54. Dilate(C, If[9 < n ≤ 10, 10 - n, 0], M) → C'_2
55. Segment(C, C'_2) → i_1
56. Dilate(D, If[10 < n ≤ 11, 11 - n, 0], N) → D'_3
57. Segment(D, D'_3) → j_1
58. Rotate(C, If[11 < n ≤ 12, ((-(n - 11)) * δ), (-δ)], C) → C'_3
59. Rotate(C'_2, If[11 < n ≤ 12, ((-(n - 11)) * δ), (-δ)], C) → Q
60. Segment(C'_3, Q) → k_1
61. Rotate(M, If[11 < n ≤ 12, ((-(n - 11)) * δ), (-δ)], C) → M'
62. Rotate(D, If[12 < n ≤ 13, ((n - 12) * ε), ε], D) → D'_4
63. Rotate(D'_3, If[12 < n ≤ 13, ((n - 12) * ε), ε], D) → R
64. Segment(D'_4, R) → l_1