印度平方根算法:通过切割正方形求平方根的几何演示

印度平方根算法:通过切割正方形求平方根的几何演示
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2016-04-08 23:21
该范例演示了一种古老的印度平方根算法,通过物理切割正方形来逐步逼近一个数的平方根。核心数学概念是平方根、有理数逼近、线性方程以及几何中的缩放(dilation)。作图要点:使用GeoGebra的Intersect(求交点)、Polygon(构造多边形)、Textfield(输入框)和Segment(线段)命令,创建了多个正方形(poly1至poly4)及其边长变量(a,b,c,d等),通过Guess1、NextGuess等对象表示迭代猜测值,并利用InputBox1和InputBox2让用户输入初始猜测和更新值,text1至text3显示计算过程。该范例适合中学数学或数学史教学,帮助学生直观理解迭代逼近和几何与算术的联系。

GeoGebra 命令及参数

  1. Intersect(xAxis, yAxis) → A
  2. Polygon(A, (Guess1, 0), 4) → poly1, a, b, c, d, B, C
  3. Polygon(A, (Guess2, 0), 4) → poly2, e, f, g, n, D, E
  4. Polygon(A, (Guess3, 0), 4) → poly3, h, i, j, p, F, G
  5. Polygon(A, (Guess4, 0), 4) → poly4, k, l, m, q, H, I
  6. Textfield(Guess1) → InputBox1
  7. Textfield(N) → InputBox2
  8. Polygon(A, (Guess5, 0), 4) → poly5, r, s, t, a_1, J, K
  9. Polygon(A, (Guess6, 0), 4) → poly6, b_1, c_1, d_1, e_1, L, M
  10. Segment((Guess2, 0), (Guess2, Guess1)) → f_1
  11. Segment((Guess3, 0), (Guess3, Guess2)) → g_1
  12. Segment((Guess4, 0), (Guess4, Guess3)) → h_1
  13. Segment((Guess5, 0), (Guess5, Guess4)) → i_1
  14. Segment((Guess6, 0), (Guess6, Guess5)) → j_1
  15. Segment((0, Guess2), (Guess1, Guess2)) → k_1
  16. Segment((0, Guess3), (Guess2, Guess3)) → l_1
  17. Segment((0, Guess4), (Guess3, Guess4)) → m_1
  18. Segment((0, Guess5), (Guess4, Guess5)) → n_1
  19. Segment((0, Guess6), (Guess5, Guess6)) → p_1