分数除法4:1除以a/b(商除法)

分数除法4:1除以a/b(商除法)
几何画板及绘图内容加载中,请稍等……
2012-07-18 15:17
①本范例演示了1除以分数a/b等于b/a的图形化解释,并推广到x除以a/b等于x乘以b/a;②核心数学概念包括分数除法、商除法、分数乘法、倒数;③作图要点使用了GeoGebra命令:Point, Min, Max, Segment, Polygon, Sequence, If;对象:a, D, E, G, F, a', b', gcd, A, s, f_1, B, w, l, m, n, p, q, r, t, a_1, b_1, c_1, d_1, g_1, h_1, i_1, f, C, poly2, poly2_1, poly2_2, poly2_3, poly2_4, text3, text4, number, text10, e, j_1;④适合初中数学教学,用于理解和应用分数除法运算规则。

GeoGebra 命令及参数

  1. Point(Segment[(x(E) + 0.1, y(E)), (x(E) + 1, y(E))]) → G
  2. Point(Segment[(x(D) + 0.1, y(D)), (x(D) + 0.5, y(D))]) → F
  3. Min(round((x(G) - x(E)) / 0.1), (2 * a')) → b'
  4. Max(Sequence[If[Mod[(a * a'), i] ≤ 0 ∧ Mod[b', i] ≤ 0, i, 1], i, 1, Min[(a * a'), b']]) → gcd
  5. Segment((0, 1), (x(A), y(A))) → f_1
  6. Point(f_1) → B
  7. Segment(A, (x(A) + a, y(A))) → l
  8. Segment((x(A), y(A) + w), (x(A) + a, y(A) + w)) → m
  9. Segment(A, (x(A), y(A) + w)) → n
  10. Segment((x(A) + 9, y(A)), (x(A) + 9, y(A) + w)) → p
  11. Segment((x(A) + 8, y(A)), (x(A) + 8, y(A) + w)) → q
  12. Segment((x(A) + 7, y(A)), (x(A) + 7, y(A) + w)) → r
  13. Segment((x(A) + 6, y(A)), (x(A) + 6, y(A) + w)) → t
  14. Segment((x(A) + 5, y(A)), (x(A) + 5, y(A) + w)) → a_1
  15. Segment((x(A) + 4, y(A)), (x(A) + 4, y(A) + w)) → b_1
  16. Segment((x(A) + 3, y(A)), (x(A) + 3, y(A) + w)) → c_1
  17. Segment((x(A) + 2, y(A)), (x(A) + 2, y(A) + w)) → d_1
  18. Segment((x(A) + 10, y(A)), (x(A) + 10, y(A) + w)) → g_1
  19. Segment((x(A) + 11, y(A)), (x(A) + 11, y(A) + w)) → h_1
  20. Segment((x(A) + 12, y(A)), (x(A) + 12, y(A) + w)) → i_1
  21. Segment((x(B) + b' / a', y(B)), (x(B) + a, y(B))) → f
  22. Point(f) → C
  23. Polygon(B, ((floor((a' * x(C) / b')) * b' / a'), y(B)), ((floor((a' * x(C) / b')) * b' / a'), y(B) + 1), (x(B), y(B) + 1)) → poly2, poly2_1, poly2_2, poly2_3, poly2_4
  24. Segment((x(A) + 1, y(A)), (x(A) + 1, y(A) + w)) → e
  25. Segment(E, (x(E) + 1, y(E))) → j_1
  26. Segment(D, F) → l_1
  27. Polygon(B, (x(B) + 1, y(B)), (x(B) + 1, y(B) + 1), (x(B), y(B) + 1)) → poly1, poly1_1, poly1_2, poly1_3, poly1_4
  28. Sequence(Segment[(k / a', y(B)), (k / a', y(B) + 1)], k, 1, a' - 1) → list2
  29. Sequence(Segment[(k / a', y(B)), (k / a', y(B) + 1)], k, 1, (floor((a' * x(C) / b')) * b') - 1) → list3
  30. Segment(((floor((a' * x(C) / b')) * b' / a'), y(B)), C) → h
  31. Segment(((floor((a' * x(C) / b')) * b' / a'), y(B) + 1), (x(C), y(C) + 1)) → i
  32. Sequence(Segment[(k / a', y(B)), (k / a', y(B) + 1)], k, 1, floor((a' * x(C))) - 1) → list4
  33. Sequence(Segment[((k * b' / a'), y(B)), ((k * b' / a'), y(B) + 1)], k, 1, floor((a' * x(C) / b')) - 1) → list1
  34. Polygon(((floor((a' * x(C) / b')) * b' / a'), y(B)), C, (x(C), y(C) + 1), ((floor((a' * x(C) / b')) * b' / a'), y(B) + 1)) → poly3, poly3_1, poly3_2, poly3_3, poly3_4
  35. Polygon(B, (b' / a', y(B)), (b' / a', y(B) + 1), (x(B), y(B) + 1)) → poly4, poly4_1, poly4_2, poly4_3, poly4_4
  36. Segment(((floor((a' * x(C) / b')) * b' / a'), y(B)), ((floor((a' * x(C) / b')) * b' / a') + b' / a', y(B))) → b
  37. Segment(((floor((a' * x(C) / b')) * b' / a'), y(B) + 1), ((floor((a' * x(C) / b')) * b' / a') + b' / a', y(B) + 1)) → c
  38. Segment(((floor((a' * x(C) / b')) * b' / a') + b' / a', y(B)), ((floor((a' * x(C) / b')) * b' / a') + b' / a', y(B) + 1)) → d
  39. Sequence(Segment[((floor((a' * x(C) / b')) * b' / a') + k / a', y(B)), ((floor((a' * x(C) / b')) * b' / a') + k / a', y(B) + 1)], k, 1, b' - 1) → list5
  40. Segment(E, (Min[x(G), x(E) + (0.2 * a')], y(G))) → m_1
  41. Segment(D, (x(D) + 0.5, y(D))) → e_1
  42. Polygon(A, (x(A) + a, y(A)), (x(A) + a, y(A) + a), (x(A), y(A) + a)) → poly5, a_2, k_1, n_1, p_1
  43. Segment((x(C), Min[y(B) + 1, 2.5]), (x(C), 2.5)) → k
  44. Polygon((x(B) + 1, y(B)), (x(B) + 2, y(B)), (x(B) + 2, y(B) + 1), (x(B) + 1, y(B) + 1)) → poly6, poly6_4, poly6_1, poly6_2, poly6_3
  45. Sequence(Segment[(k / a' + 1, y(B)), (k / a' + 1, y(B) + 1)], k, 1, a' - 1) → list7
  46. Sequence(Segment[(j / a', y(A)), (j / a', y(A) + 1)], j, 1, a' - 1) → list6
  47. If(b' < a', text40_1, If[b' > a' ∧ b' ≠ (2 * a'), text40_3, text40_2]) → text40