求平方根的几何构造演示

求平方根的几何构造演示
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2016-02-26 16:27
该范例通过几何作图直观演示了求平方根的数学过程,将抽象的算术运算转化为可视化的图形构造。核心数学概念涉及平方根、直角三角形、梯形、序列与数列以及利息计算等,但主要聚焦于利用几何关系(如直角三角形中的比例或面积关系)来求解平方根。作图要点包括使用GeoGebra的旋转(Rotate)、中点(Midpoint)、垂直文本(VerticalText)、线段(Segment)、向量(Vector)和角点(Corner)等命令,并创建了多个多边形(poly2至poly8)、文本标签(text1至text12)以及按钮(button1)来交互控制。该范例适合中学数学或大学预科阶段的学生,用于理解平方根的几何意义,也可作为数学实验或探究性学习的素材,帮助学生在动态操作中深化对平方根概念的理解。

GeoGebra 命令及参数

  1. Rotate(Polygon[O, O + (a', 0), O + (a', (-a')), O + (0, (-a'))], 0, (1, -4)) → poly2
  2. Rotate(Polygon[O + (a', 0), O + (a' + b', 0), O + (a' + b', (-a')), O + (a', (-a'))], 0, (0, 0)) → poly3
  3. Rotate(Polygon[O + (a' + b', (-a')), O + (a', (-a')), O + (a', (-a') - b'), O + (a' + b', (-a') - b')], 0, (0, 0)) → poly4
  4. Rotate(Polygon[O + (a', (-a')), O + (0, (-a')), O + (0, (-a') - b'), O + (a', (-a') - b')], 0, (0, 0)) → poly5
  5. Rotate(Polygon[O + (a' + b', 0), O + (a' + b', (-a') - b'), O + (a' + b' + c', (-a') - b'), O + (a' + b' + c', 0)], 0, (16, 7)) → poly6
  6. Rotate(Polygon[O + (a' + b', (-a') - b'), O + (a' + b' + c', (-a') - b'), O + (a' + b' + c', (-a') - b' - c'), O + (a' + b', (-a') - b' - c')], 0, (0, 0)) → poly7
  7. Rotate(Polygon[O + (a' + b', (-a') - b'), O + (a' + b', (-a') - b' - c'), O + (0, (-a') - b' - c'), O + (0, (-a') - b')], 0, (0, 0)) → poly8
  8. Midpoint(O, O + (a', (-a'))) → A
  9. Midpoint(O + (a', 0), O + (a' + b', (-a'))) → B
  10. Midpoint(O + (a', (-a')), O + (0, (-a') - b')) → C
  11. Midpoint(O + (a' + b', (-a')), O + (a', (-a') - b')) → D
  12. Midpoint(O + (a' + b', 0), O + (a' + b' + c', (-a') - b')) → E
  13. Midpoint(O + (a' + b', (-a') - b'), O + (0, (-a') - b' - c')) → F
  14. Midpoint(O + (a' + b', (-a') - b'), O + (a' + b' + c', (-a') - b' - c')) → G
  15. VerticalText("c(a+b)") → text5
  16. Segment(O + (0, 1), O + (0, 3)) → d
  17. Segment(O + (a', 1), O + (a', 3)) → e
  18. Vector(O + (0, 2), O + (a', 2)) → u
  19. Vector(O + (a', 2), O + (0, 2)) → v
  20. Segment(O + (-1, 0), O + (-3, 0)) → f
  21. Segment(O + (-1, (-a')), O + (-3, (-a'))) → g
  22. Vector(O + (-2, 0), O + (-2, (-a'))) → w
  23. Vector(O + (-2, (-a')), O + (-2, 0)) → h
  24. Segment(O + (a' + b', 1), O + (a' + b', 3)) → i
  25. Vector(O + (a', 2), O + (a' + b', 2)) → j
  26. Vector(O + (a' + b', 2), O + (a', 2)) → k
  27. Segment(O + (-1, (-a') - b'), O + (-3, (-a') - b')) → l
  28. Vector(Midpoint[g], Midpoint[l]) → m
  29. Vector(Midpoint[l], Midpoint[g]) → p
  30. Segment(O + (a' + b' + c', 1), O + (a' + b' + c', 3)) → q
  31. Vector(Midpoint[i], Midpoint[q]) → r
  32. Vector(Midpoint[q], Midpoint[i]) → s
  33. Segment(O + (-1, (-a') - b' - c'), O + (-3, (-a') - b' - c')) → t
  34. Vector(Midpoint[l], Midpoint[t]) → u_1
  35. Vector(Midpoint[t], Midpoint[l]) → v_1
  36. Corner(1) → C_1
  37. Corner(2) → C_2
  38. Corner(3) → C_3
  39. Corner(4) → C_4
  40. Corner(5) → C_5