无字证明:奇数和

无字证明:奇数和
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2020-03-24 04:00
①本范例通过动态图形演示奇数和的累加构成一个正方形的现象;②涉及的核心数学概念包括数列、几何图形构造和代数证明;③作图要点:运用了Sequence(数列)、Vector(向量)、Join(连接)、Polygon(多边形)、Element(元素)、Midpoint(中点)等GeoGebra命令;④适合初中及以上学生学习数列求和、几何证明及数学可视化。

GeoGebra 命令及参数

  1. Sequence(Sequence[(i, j), i, 0, n - 1 - j], j, 0, n - 1) → list1
  2. Sequence(Sequence[(n + 1 - j + i, j - 1), i, 0, n - 1 - j], j, 1, n - 1) → list2
  3. Vector((-1, 1)) → u
  4. Join(Sequence[Sequence[Translate[(n + 1 - j + i, j - 1), Vector[((k * u) * (i + 1))]], i, 0, n - 1 - j], j, 1, n - 1]) → list3
  5. Sequence(Polygon[(0, n - 1), (0, n - 1 - i), 4], i, 1, n - 1) → listPoly
  6. Sequence(Sequence[(i, j), i, 0, n - 1 - j], j, 0, n - 1, 2) → l1
  7. Sequence(Sequence[Translate[(n + 1 - j + i, j - 1), Vector[((k * u) * (i + 1))]], i, 0, n - 1 - j], j, 1, n - 1, 2) → l3
  8. Sequence(Segment[(0, i), ((2 * n) - 2 - (2 * i), i)], i, 0, n - 2) → listSegment
  9. Sequence(Segment[(0, i), ((2 * n) - (n + 1) - i, i)], i, 0, n - 2) → l2
  10. Sequence(((2 * n) - (n + 1) - i, i), i, 0, n - 2) → l5
  11. Join(Sequence[Sequence[Translate[(n + 1 - j + i, j - 1), Vector[((k * u) * (i + 1))]], i, 0, n - 1 - j], j, 1, n - 1, 1]) → l4
  12. Vector(Element[l5, 1], Element[list3, 1]) → v
  13. Sequence(Translate[Element[l5, i], Vector[((n - i) * v)]], i, 1, Length[l5]) → l6
  14. Sequence(Segment[Element[l5, i], Element[l6, i]], i, 1, Length[l5]) → l7
  15. Polygon((0, n - 1), (0, 0), 4) → poly1
  16. Sequence(Text[(2 * k) + 1, (-1.1, n - k - 1.1)], k, 0, n - 1) → l8
  17. Sequence(Text[(2 * k) + 1 + "+"], k, 0, n - 1) → l9
  18. Sequence(A + ((1.15 * i), 0), i, 0, n) → l10
  19. Sequence(Text[Element[l8, k] + " + ", Element[l10, k]], k, 1, n) → l11
  20. Element(l5, 1) → MM
  21. Element(l6, 1) → NN
  22. Midpoint(B, C) → D
  23. Vector(D, B) → w
  24. Vector(D, C) → a