可修改的立体:平行于y轴的等腰三角形截面

可修改的立体:平行于y轴的等腰三角形截面
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2019-05-09 00:47
这个范例演示了一个可修改的立体,其平行于y轴的截面是等腰三角形,且底角可调。涉及的核心数学概念包括立体几何、解析几何和微积分中的截面分析。作图要点使用了GeoGebra命令如Intersect(相交)、Segment(线段)、Midpoint(中点)、Line(直线)、Rotate(旋转)、Ray(射线)、Sphere(球体)、Polygon(多边形)、Textfield(文本框)、Angle(角度)、CurveCartesian(笛卡尔曲线)、Surface(曲面)等。适合高中及以上学生学习和理解复杂几何体及其截面性质。

GeoGebra 命令及参数

  1. Intersect(lower, h, (-8, -14)) → C
  2. Intersect(upper, h, (-8, 10.145500033808613)) → B
  3. Segment(C, B) → q
  4. Intersect(upper, q, (-8, 10.145500033808613)) → G
  5. Midpoint(C, G) → T
  6. Line(T, T + (1, 0, 0)) → l_1
  7. Rotate(C, (-α), G, l_1) → C'
  8. Ray(G, C') → f_2
  9. Rotate(G, α, C, l_1) → G'
  10. Ray(C, G') → e_1
  11. Intersect(f_2, e_1) → B_1
  12. Segment(H, I) → s_1
  13. Midpoint(s_1) → E
  14. Line(E, E + (1, 0, 0)) → r_1
  15. Rotate(I, (-α), H, r_1) → I'
  16. Ray(H, I') → b_1
  17. Rotate(H, α, I, r_1) → H'
  18. Ray(I, H') → a_1
  19. Intersect(b_1, a_1) → A_1
  20. Segment(J, K) → q_1
  21. Midpoint(q_1) → F
  22. Line(F, F + (1, 0, 0)) → c
  23. Rotate(K, (-α), J, c) → K'
  24. Ray(J, K') → p_1
  25. Rotate(J, α, K, c) → J'
  26. Ray(K, J') → m_1
  27. Intersect(m_1, p_1) → Z
  28. Line(B, D) → i
  29. Sphere(B, d) → e
  30. Polygon(C, G, B_1) → q1, f_1, g_1, n_1
  31. Segment(C, B) → p
  32. Polygon(K, J, Z) → q2, l, m, n
  33. Polygon(H, I, A_1) → q3, r, s, t
  34. Textfield(upper) → InputBox1
  35. Textfield(lower) → InputBox2
  36. Textfield(a) → InputBox3
  37. Textfield(b) → InputBox4
  38. Segment(C, G) → k_1
  39. Segment(K, Z) → f
  40. Segment(J, Z) → g
  41. Segment(A_1, I) → c_1
  42. Segment(A_1, H) → d_1
  43. Segment(C, B_1) → i_1
  44. Segment(B_1, G) → j_1
  45. Angle(G, C, B_1) → β
  46. Angle(B_1, G, C) → γ
  47. CurveCartesian(t, lower(t) + (0.5 * (upper(t) - lower(t))), ((0.5 * (upper(t) - lower(t))) * tan(α)), t, a, b) → j
  48. Surface(u, ((0.5 * (upper(u) - lower(u))) * v) + lower(u), (((0.5 * (upper(u) - lower(u))) * tan(α)) * v), u, a, b, v, 0, 1) → k
  49. Surface(u, ((0.5 * (upper(u) - lower(u))) * v) + (0.5 * (lower(u) + upper(u))), (((-0.5 * (upper(u) - lower(u))) * tan(α)) * v) + ((0.5 * (upper(u) - lower(u))) * tan(α)), u, a, b, v, 0, 1) → o