直角三角形的一个趣味性质

直角三角形的一个趣味性质
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2018-03-06 05:05
①本范例演示直角三角形内接正方形与边长关系的动态几何现象;②涉及核心数学概念:直角三角形、正方形、解析几何、连续性;③作图要点:使用 GeoGebra 命令 Point(点)、Intersect(交点)、Segment(线段)、OrthogonalLine(垂线)、Line(直线)、Polygon(多边形)、Midpoint(中点)、Angle(角度);④适合高中及以上数学学习者探索几何性质与函数关系。

GeoGebra 命令及参数

  1. Point(yAxis) → A_2
  2. Point(xAxis) → B_2
  3. Intersect(xAxis, yAxis) → C
  4. Segment(B_2, C) → f
  5. Segment(A_2, C) → g
  6. Segment(B_2, A_2) → h
  7. OrthogonalLine(C, h) → i
  8. Intersect(i, h) → D
  9. Segment(C, D) → j
  10. Segment(A_2, D) → k
  11. Segment(D, B_2) → l
  12. Point(k) → B
  13. Point(l) → A
  14. Point(f) → G
  15. Line(G, l) → m
  16. Intersect(m, g) → H
  17. Segment(G, H) → n
  18. Polygon(A_2, G, C) → d1, c, a, g_1
  19. Polygon(C, H, B_2) → d3, b, c_1, h_1
  20. Segment(L, M) → t
  21. OrthogonalLine(B_2, xAxis) → d
  22. Point(d) → N
  23. Point(d) → O
  24. Segment(N, O) → j_1
  25. Midpoint(t) → P
  26. Midpoint(j_1) → Q
  27. Segment(P, Q) → l_1
  28. OrthogonalLine(A_2, yAxis) → m_1
  29. Point(m_1) → R
  30. Point(m_1) → S
  31. Point(xAxis) → T
  32. Point(xAxis) → U
  33. Segment(T, U) → n_1
  34. Segment(R, S) → p_1
  35. Midpoint(R, S) → V
  36. Midpoint(T, U) → W
  37. Segment(V, W) → q_1
  38. OrthogonalLine(A_2, k) → r_1
  39. OrthogonalLine(B_2, l) → s_1
  40. Point(r_1) → Z
  41. Point(r_1) → A_1
  42. Point(s_1) → B_1
  43. Point(s_1) → C_1
  44. Segment(Z, A_1) → t_1
  45. Segment(B_1, C_1) → a_1
  46. Midpoint(Z, A_1) → D_1
  47. Midpoint(B_1, C_1) → E_1
  48. Segment(D_1, E_1) → b_1
  49. Segment(B, D) → d_1
  50. Segment(D, B_2) → e_1
  51. Angle(D, C, B) → α
  52. Angle(D, A, C) → β
  53. Angle(C, B, D) → γ
  54. Angle(A, C, D) → δ
  55. Angle(B, D, C) → ε
  56. Polygon(B, D, C) → t1, c_2, e, d_2
  57. Polygon(C, D, A) → t2, f_1, c_3, d_3