圆心在弦上的内接角定理证明练习

圆心在弦上的内接角定理证明练习
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2017-07-25 22:56
①本范例演示圆心位于内接角弦上的内接角定理证明过程;②涉及核心数学概念包括圆、内接角、圆心角、几何证明;③作图要点:使用 GeoGebra 命令 Circle(圆)、Point(点)、CircleArc(圆弧)、Line(直线)、Intersect(交点)、Segment(线段)、Angle(角)、Rotate(旋转)、CircleSector(扇形)、Dilate(缩放)、Vector(向量)、Polygon(多边形)、Translate(平移);④适合高中数学教学,用于帮助学生理解和掌握内接角定理的证明方法。

GeoGebra 命令及参数

  1. Circle(O, B_1) → c
  2. Point(c) → B
  3. Point(c) → C_1
  4. CircleArc(O, B, C_1) → d
  5. Point(d) → A
  6. Line(A, O) → f_1
  7. Intersect(c, f_1) → Q, C
  8. Point(d) → F
  9. Segment(O, C_1) → a
  10. Segment(A, B) → g
  11. Segment(F, C_1) → h
  12. Segment(F, B) → i
  13. Angle(C_1, O, B) → α
  14. Rotate(C_1, α / 2, O) → C'
  15. Angle(C_1, O, C') → β
  16. Segment(O, C') → j
  17. Segment(A, C) → f
  18. Circle(A, (0.25 * Distance[O, B_1])) → k
  19. Intersect(k, f, 1) → G
  20. Intersect(k, g, 1) → H
  21. Circle(F, (0.25 * Distance[O, B_1])) → p
  22. Intersect(p, h, 1) → J
  23. Intersect(p, i, 1) → K
  24. CircleSector(A, G, H) → q
  25. CircleSector(F, J, K) → r
  26. Dilate(A, If[0 < l ≤ 1, 1 - l, 0], O) → E'
  27. Vector(A, E') → u
  28. Line(A, a) → m
  29. Intersect(k, m, 2) → L
  30. Angle(L, A, G) → γ
  31. Dilate(A, If[2 < l ≤ 3, 3 - l, 0], O) → E'_1
  32. Vector(A, E'_1) → v
  33. Line(A, j) → n
  34. Intersect(k, n, 2) → M
  35. Angle(M, A, G) → δ
  36. Circle(O, (0.25 * Distance[O, B_1])) → t
  37. Intersect(t, a, 1) → N
  38. Intersect(t, j, 1) → O_1
  39. Intersect(t, c, 1) → I
  40. Intersect(k, f_1) → S, T
  41. CircleArc(O, C, B) → e
  42. Intersect(t, f_1) → U, V
  43. Angle(G, A, H) → ε
  44. Segment(O, C) → s
  45. Segment(A, O) → g_1
  46. Dilate(A, If[-1 < l ≤ 0, (-l), 0], O) → E'_2
  47. Segment(A, E'_2) → i_1
  48. Dilate(O, If[0 < l ≤ 1, 1 - l, 0], C) → A'
  49. Segment(O, A') → j_1
  50. Angle(C, O, B) → η
  51. Rotate(O, If[1 < l ≤ 2, ((l - 1) * η), η], O) → A'_1
  52. Rotate(A', If[1 < l ≤ 2, ((l - 1) * η), η], O) → A''
  53. Segment(A'_1, A'') → k_1
  54. Rotate(A'_1, If[2 < l ≤ 3, ((l - 2) * (π - η)), π - η], O) → P
  55. Rotate(A'', If[2 < l ≤ 3, ((l - 2) * (π - η)), π - η], O) → A'''
  56. Segment(P, A''') → b
  57. Polygon(O, B, A) → poly1, e_1, a_1, d_1
  58. Circle(B, Radius[k]) → c_1
  59. Intersect(c_1, k_1) → W,
  60. Angle(A, B, O) → ζ
  61. Rotate(W, If[3 < l ≤ 4, ((-(l - 3)) * ζ), (-ζ)], B) → W'
  62. CircleSector(B, W', W) → h_1
  63. CircleArc(O, B, C) → p_1
  64. Dilate(A, If[0 < o ≤ 1, 1 - o, 0], O) → E'_3
  65. Vector(A, E'_3) → w
  66. Translate(q, w) → q'
  67. Line(A, k_1) → l_1
  68. Point(l_1) → Z
  69. Angle(B, A, Z) → θ
  70. Rotate(q', If[1 < o ≤ 2, ((o - 1) * θ), θ], O) → q''
  71. Dilate(A, If[2 < o ≤ 3, 3 - o, 0], O) → E'_4
  72. Vector(A, E'_4) → u_1
  73. Translate(q, u_1) → q'_1