无字证明:度量关系(1)

无字证明:度量关系(1)
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2020-04-22 14:55
①本范例通过动态图形演示矩形与线性函数间的度量关系;②涉及核心数学概念包括解析几何、向量、旋转与平移;③构造要点:运用了Circle(圆)、Midpoint(中点)、Polygon(多边形)、OrthogonalLine(垂线)、Intersect(交点)、Angle(角度)、Segment(线段)、Rotate(旋转)、Translate(平移)、Vector(向量)、Centroid(重心)等命令与对象;④适合高中及以上数学学习者,用于理解几何变换与度量性质。

GeoGebra 命令及参数

  1. Circle(C, B) → c
  2. Midpoint(C, B) → C_1
  3. Circle(C_1, B) → d
  4. Point(d) → A
  5. Polygon(C, B, A) → t1, d_1, a, b
  6. OrthogonalLine(A, d_1) → f
  7. Intersect(d_1, f) → H
  8. Angle(C, A, B) → α
  9. Angle(B, H, A) → β
  10. Segment(A, H) → g
  11. Segment(H, B) → h
  12. Rotate(H, If[a < π / 2, a / (π / 2), π / 2], H) → H'
  13. Rotate(B, If[Animation < π / 2, ((-Animation)) / (π / 2), ((-π)) / 2], H) → B'
  14. Segment(H', B') → h'
  15. Translate(H', Vector[(If[π / 2 < Animation < 5, (Animation - π / 2) / 5, 1] * Vector[H, C])]) → H''
  16. Translate(B', Vector[(If[π / 2 < Animation < 5, (Animation - π / 2) / 5, 1] * Vector[H, C])]) → B''
  17. Segment(H'', B'') → h''
  18. Segment(H, C) → l
  19. Translate(H, Vector[(If[π / 2 < Animation < 5, (Animation - π / 2) / 5, 1] * Vector[H, B'])]) → H'_1
  20. Translate(C, Vector[(If[π / 2 < Animation < 5, (Animation - π / 2) / 5, 1] * Vector[H, B'])]) → C'
  21. Segment(H'_1, C') → l'
  22. Polygon(C, H, B', B'') → q1, c_1, h_1, b', b''
  23. Rotate(H, If[5 < Animation < 5 + π / 2, (Animation - 5) / (π / 2), π / 2], A) → A'
  24. Segment(A', A) → i
  25. Rotate(A, If[5 < Animation < 5 + π / 2, ((-(Animation - 5))) / (π / 2), ((-π)) / 2], H) → A'_1
  26. Segment(H, A'_1) → j
  27. Rotate(A, If[8 < Animation < 10, (Animation - 8) / (π / 2), π / 2], A') → A'_2
  28. Segment(A', A'_2) → k
  29. Polygon(A, A', A'_1, H) → q2, a_1, a', a'_1, h_2
  30. Vector(A, C) → u
  31. Vector(H, B'') → v
  32. Vector(A'_2, B') → w
  33. Vector(A', H) → e
  34. Translate(A, Vector[(If[11 < Animation < 14, (Animation - 11) / 3, 1] * u)]) → A'_3
  35. Translate(H, Vector[(If[11 < Animation < 14, (Animation - 11) / 3, 1] * v)]) → H'_2
  36. Translate(A', Vector[(If[11 < Animation < 14, (Animation - 11) / 3, 1] * e)]) → A''
  37. Translate(A'_2, Vector[(If[11 < Animation < 14, (Animation - 11) / 3, 1] * w)]) → D
  38. Polygon(A'_3, H'_2, D, A'') → q3, a'_3, h'_2, d_2, a''
  39. Centroid(q2) → E
  40. Centroid(q1) → F