两割线外角交互探究

两割线外角交互探究
几何画板及绘图内容加载中,请稍等……
2019-06-27 07:19
①本范例演示从圆外引出的两割线所夹角的动态变化;②涉及核心概念:圆、割线、角、交互式几何探究;③作图要点:运用了PointIn, Semicircle, Circle, Intersect, CircleArc, Point, Segment, Min, Dilate, Angle, Rotate, Vector, CircleSector, Translate, Line, Midpoint等命令与对象;④适合高中数学几何教学,用于理解割线定理及动态几何关系。

GeoGebra 命令及参数

  1. PointIn(a) → C
  2. Semicircle(C, A) → e
  3. Semicircle(A, C) → d
  4. Circle(A, B) → c
  5. Intersect(c, e, 1) → E
  6. Intersect(c, d, 1) → D
  7. CircleArc(A, E, D) → g
  8. CircleArc(A, D, E) → f
  9. Point(f) → F
  10. Segment(C, F) → i
  11. Intersect(g, i, 1) → H
  12. CircleArc(A, F, E) → h
  13. Point(h) → G
  14. Segment(C, G) → j
  15. Intersect(g, j, 1) → I
  16. CircleArc(A, H, I) → h_2
  17. Min({Distance[A, B], Distance[C, H], Distance[C, I]}) → k
  18. Circle(A, (0.4 * k)) → p
  19. Segment(A, F) → l
  20. Segment(A, G) → m
  21. Intersect(p, l, 1) → J
  22. Segment(A, I) → n
  23. Segment(A, H) → q
  24. Intersect(p, n, 1) → K
  25. Intersect(p, q, 1) → L
  26. Dilate(A, If[0 < b ≤ 1, 1 - b, 0], F) → A'
  27. Dilate(A, If[0 < b ≤ 1, 1 - b, 0], G) → A'_1
  28. Dilate(A, If[0 < b ≤ 1, 1 - b, 0], H) → A'_2
  29. Dilate(A, If[0 < b ≤ 1, 1 - b, 0], I) → A'_3
  30. Angle(F, C, G) → ε
  31. Rotate(J, If[8 < b ≤ 9, ((b - 8) * ε), ε], A) → J'_1
  32. Dilate(A, If[10 < b ≤ 11, 11 - b, 0], C) → A'_7
  33. Vector(A, A'_7) → u
  34. CircleArc(A, F, G) → t_1
  35. CircleArc(A, I, H) → c_2
  36. CircleArc(A, H, F) → d_2
  37. CircleArc(A, G, I) → e_2
  38. CircleArc(A, G, F) → f_2
  39. Point(h_2) → R
  40. Point(f_2) → Q
  41. Segment(R, H) → a_1
  42. Segment(R, I) → b_1
  43. Segment(Q, F) → g_2
  44. Segment(Q, G) → i_2
  45. Min({Distance[Q, G], Distance[Q, F], Distance[R, F], Distance[R, G], Distance[C, H], Distance[C, I]}) → o
  46. Circle(R, (0.5 * o)) → k_2
  47. Circle(Q, (0.5 * o)) → p_2
  48. Intersect(p_2, g_2, 1) → S
  49. Intersect(k_2, b_1, 1) → P
  50. Angle(P, R, H) → ζ
  51. Angle(S, Q, G) → μ
  52. Angle(H, C, I) → κ
  53. Dilate(Q, If[0 < b ≤ 1, 1 - b, 0], G) → Q'
  54. Dilate(Q, If[0 < b ≤ 1, 1 - b, 0], F) → Q'_1
  55. Segment(Q, Q') → s
  56. Segment(Q, Q'_1) → t
  57. Dilate(R, If[1 < b ≤ 2, 2 - b, 0], H) → R'
  58. Dilate(R, If[1 < b ≤ 2, 2 - b, 0], I) → R'_1
  59. Segment(R, R') → r
  60. Segment(R, R'_1) → f_1
  61. Rotate(S, If[2 < b ≤ 3, ((b - 2) * μ), μ], Q) → S'_1
  62. Rotate(P, If[3 < b ≤ 4, ((b - 3) * ζ), ζ], R) → P'
  63. CircleSector(R, P, P') → c_1
  64. CircleSector(Q, S, S'_1) → d_1
  65. Dilate(R, If[5 < b ≤ 6, 6 - b, 0], Q) → R'_2
  66. Vector(R, R'_2) → v
  67. Translate(c_1, v) → e_1
  68. Line(Q, r) → g_1
  69. Point(g_1) → M
  70. Intersect(p_2, i_2) → N,
  71. Rotate(N, (-ζ), Q) → N'
  72. Angle(M, Q, N) → α
  73. Rotate(e_1, If[5 < b ≤ 6, ((b - 5) * α), α], R'_2) → h_1
  74. Rotate(S, If[6 < b ≤ 7, ((b - 6) * (μ - ζ)), μ - ζ], Q) → S'
  75. CircleSector(Q, S, S') → k_1
  76. Midpoint(Q, C) → O
  77. Rotate(Q, If[8 < b ≤ 9, ((-(b - 8)) * π), (-π)], O) → Q'_2
  78. Vector(Q, Q'_2) → w
  79. Translate(k_1, w) → p_1
  80. Line(C, t) → i_1
  81. Point(i_1) → T
  82. Angle(T, C, F) → β
  83. Rotate(p_1, If[8 < b ≤ 9, ((-(b - 8)) * ((2 * π) - β)), β - (2 * π)], Q'_2) → q_1
  84. CircleArc(A, H, F) → r_1
  85. CircleArc(A, G, I) → s_1

AI 绘图提示语参考

绘制一个圆,圆外一点引出两条割线,分别与圆相交。在圆上取两个动点,连接圆外点与动点形成两条线段,线段与圆再次相交。用圆弧连接圆上的交点,形成动态区域。在圆内构造一个小圆,用于显示角度。从圆外点向两个动点作射线,并在小圆上标记交点。用线段连接圆上各交点,形成可拖动的几何图形,展示两割线夹角的变化。
以上提示语为根据原始绘图命令整理而来,仅供参考。