四分之一圆的惊喜

四分之一圆的惊喜
几何画板及绘图内容加载中,请稍等……
2017-06-01 22:07
①这个范例动态演示了四分之一圆内角度、线段与概率统计问题的关系;②涉及核心数学概念包括角度、圆、假设检验、条件概率、中值、几何变换、不定积分;③作图要点提炼自构造摘要,使用了Circle(圆)、Rotate(旋转)、Angle(角度)、Line(线)、Intersect(交点)、Ray(射线)、Segment(线段)、CircleSector(扇形)、CircleArc(圆弧)、Dilate(缩放)、Point(点)、Polygon(多边形)等GeoGebra命令/对象;④适合高中及以上数学学习者,用于理解几何变换与概率统计的综合应用。

GeoGebra 命令及参数

  1. Circle(A, B) → c
  2. Rotate(B, 45°, A) → B'
  3. Angle(B, A, B') → α
  4. Line(B', f) → h
  5. Line(B', g) → i
  6. Intersect(f, xAxis) → D
  7. Intersect(i, f) → E
  8. Intersect(g, h) → F
  9. Line(F, B) → j
  10. Angle(B, F, B') → β
  11. Rotate(B', β, F) → B''
  12. Angle(B', F, B'') → γ
  13. Ray(F, B'') → k
  14. Intersect(c, k, 1) → G
  15. Segment(F, G) → l
  16. Circle(F, (0.5 * l)) → d
  17. Intersect(d, l, 1) → H
  18. Intersect(d, h, 2) → I
  19. CircleSector(F, I, H) → e
  20. Circle(A, (0.2 * a)) → p
  21. Ray(A, B') → m
  22. Intersect(p, g) → J, K
  23. Intersect(p, f) → L, M
  24. Intersect(p, m, 1) → N
  25. CircleSector(A, N, J) → q
  26. Angle(C, A, O) → δ
  27. Angle(B', E, O) → ε
  28. Ray(A, O) → n
  29. CircleArc(A, B, C) → r
  30. Ray(A, B) → s
  31. Ray(A, C) → t
  32. Dilate(A, If[0 < o ≤ 1, 1 - o, 0], B') → A'
  33. Segment(A, A') → f_1
  34. Point(h) → P
  35. Angle(P, F, A) → η
  36. Ray(F, P) → g_1
  37. Dilate(B', If[1 < o ≤ 2, 2 - o, 0], E) → B''_1
  38. Dilate(B', If[1 < o ≤ 2, 2 - o, 0], F) → B''_2
  39. Segment(B', B''_1) → h_1
  40. Segment(B', B''_2) → i_1
  41. Rotate(q, If[2 < o ≤ 3, ((-(o - 2)) * π / 4), ((-π)) / 4], A) → q'
  42. Circle(F, l) → c_1
  43. Intersect(c_1, j, 2) → Q
  44. Circle(Q, l) → d_1
  45. Intersect(d_1, j, 2) → R
  46. Dilate(F, If[3 < o ≤ 4, 4 - o, 0], G) → F'
  47. Segment(F, F') → j_1
  48. Dilate(F, If[4 < o < 5, 5 - o, 0], Q) → F'_1
  49. Segment(F, F'_1) → k_1
  50. Dilate(Q, If[5 < o < 6, 6 - o, 0], R) → Q'
  51. Segment(Q, Q') → l_1
  52. Dilate(R, If[6 < o < 7, 7 - o, 0], B) → R'
  53. Segment(R, R') → m_1
  54. Rotate(e, If[7 < o ≤ 8, ((-(o - 7)) * β), (-β)], F) → e'
  55. Rotate(F, If[8 < o ≤ 9, (((-(o - 8)) * 2) * β), (-2 * β)], F) → F'_2
  56. Rotate(F', If[8 < o ≤ 9, (((-(o - 8)) * 2) * β), (-2 * β)], F) → F''
  57. Segment(F'_2, F'') → n_1
  58. Rotate(F'_2, If[9 < o ≤ 10, ((-(o - 9)) * π), (-π)], F'') → S
  59. Rotate(F'', If[9 < o ≤ 10, ((-(o - 9)) * π), (-π)], F'') → F'''
  60. Segment(S, F''') → p_1
  61. Rotate(S, If[10 < o ≤ 11, ((-(o - 10)) * π), (-π)], S) → S'
  62. Rotate(F''', If[10 < o ≤ 11, ((-(o - 10)) * π), (-π)], S) → T
  63. Segment(S', T) → q_1
  64. Ray(A, U) → r_1
  65. CircleSector(A, B, C) → e_1
  66. Polygon(A, E, B', F) → poly1, a_1, e_2, b', f_2