动态几何问题演示 by Tim Brzezinski

动态几何问题演示 by Tim Brzezinski
几何画板及绘图内容加载中,请稍等……
2017-12-18 06:26
①本范例动态演示了由 Antonio Gutierrez 在 Twitter 上提出的一个几何问题;②涉及核心数学概念包括极限、函数图像、随机变量、条件概率和参数曲线;③作图要点:运用了 Midpoint(中点)、Segment(线段)、Circle(圆)、OrthogonalLine(垂线)、Intersect(交点)、Ray(射线)、Point(点)、Angle(角度)、Rotate(旋转)、Polygon(多边形)、Line(直线)、Min(最小值)、Dilate(缩放)、CircleSector(扇形)、Vector(向量)、Translate(平移)等 GeoGebra 命令与对象;④适合高中及以上数学学习者,用于理解复杂几何问题的动态变化过程。

GeoGebra 命令及参数

  1. Midpoint(A, B) → H
  2. Segment(A, H) → r
  3. Circle(A, 2) → c
  4. Segment(A, B) → f
  5. OrthogonalLine(A, f) → g
  6. Intersect(c, g, 2) → C
  7. Ray(A, C) → h
  8. Point(h) → D
  9. Segment(D, B) → i
  10. OrthogonalLine(A, i) → m
  11. Intersect(m, i) → G
  12. Angle(G, H, A) → β
  13. Rotate(G, β / 2, H) → G'
  14. Ray(H, G') → t
  15. Segment(G, H) → s
  16. Segment(A, G) → q
  17. Intersect(q, t) → I
  18. Midpoint(H, I) → J
  19. Segment(H, J) → i_1
  20. Segment(H, I) → f_1
  21. Segment(G, B) → p
  22. Segment(D, G) → n
  23. Segment(A, D) → j
  24. Polygon(A, B, D) → t1, d, a, b
  25. Line(B, A) → k
  26. Circle(A, 2) → e
  27. Intersect(e, k) → E, F
  28. Ray(A, F) → l
  29. Angle(D, A, F) → α
  30. Min({n, p, q, r, f_1, s, i_1}) → o
  31. Angle(G, H, G') → γ
  32. Dilate(A, If[0 < u ≤ 1, 1 - u, 0], H) → A'
  33. Segment(A, A') → g_1
  34. Rotate(A, If[1 < u ≤ 2, ((-(u - 1)) * π), (-π)], H) → A'_1
  35. Rotate(A', If[1 < u ≤ 2, ((-(u - 1)) * π), (-π)], H) → A''
  36. Segment(A'_1, A'') → h_1
  37. Dilate(H, If[2 < u ≤ 3, 3 - u, 0], G) → H'
  38. Segment(H, H') → j_1
  39. Dilate(H, If[3 < u ≤ 4, 4 - u, 0], J) → H'_1
  40. Segment(H, H'_1) → k_1
  41. Circle(H, (0.45 * o)) → c_1
  42. Segment(G, H) → l_1
  43. Line(J, H) → m_1
  44. Intersect(c_1, m_1) → K, L
  45. Intersect(c_1, l_1) → M,
  46. Rotate(M, If[5 < u ≤ 6, ((u - 5) * γ), γ], H) → M'
  47. CircleSector(H, M, M') → d_1
  48. Rotate(d_1, If[7 < u ≤ 8, ((u - 7) * γ), γ], H) → e_1
  49. Midpoint(A, G) → N
  50. Dilate(H, If[8 < u ≤ 9, 9 - u, 0], N) → H'_2
  51. Vector(H, H'_2) → v
  52. Translate(e_1, v) → p_1
  53. Rotate(p_1, If[9 < u ≤ 10, ((-(u - 9)) * π / 2), ((-π)) / 2], N) → q_1
  54. Dilate(N, If[10 < u ≤ 11, 11 - u, 0], A) → N'
  55. Vector(N, N') → w
  56. Translate(q_1, w) → r_1
  57. Dilate(A, If[11 < u ≤ 12, 12 - u, 0], G) → A'_2
  58. Segment(A, A'_2) → n_1
  59. Circle(G, (0.45 * o)) → s_1
  60. Intersect(s_1, i, 2) → O
  61. Rotate(O, If[12.5 < u ≤ 13.5, ((-(u - 12.5)) * π / 2), ((-π)) / 2], G) → D'
  62. CircleSector(G, D', O) → t_1
  63. Rotate(t_1, If[14.5 < u ≤ 15.5, ((-(u - 14.5)) * π / 2), ((-π)) / 2], G) → c_2
  64. Rotate(A'_1, If[16 < u ≤ 17, ((u - 16) * (π - β)), π - β], H) → P
  65. Rotate(A'', If[16 < u ≤ 17, ((u - 16) * (π - β)), π - β], H) → A'''
  66. Segment(P, A''') → a_1