GeoGebra椭圆的射影几何构造与性质探究

GeoGebra椭圆的射影几何构造与性质探究
几何画板及绘图内容加载中,请稍等……
2020-05-02 23:02
本范例通过GeoGebra动态展示椭圆在射影几何框架下的构造与性质,演示了如何利用圆锥曲线、圆柱、棱锥等三维对象与平面相交生成椭圆,并借助镜像、中点、线段等工具构建射影对应关系。核心数学概念包括射影几何中的交比、对合、极点极线,以及椭圆作为圆锥截线的统一性质。作图要点涉及使用Intersect(求交)、Mirror(镜像)、Polygon(多边形)、PointIn(点内)、Midpoint(中点)、Segment(线段)、Point(点)、Line(直线)、Conic(圆锥曲线)、Sphere(球面)、Sequence(序列)等GeoGebra命令,并操作b、E_1、a、F_1、G_1、FF、poly5、ff'、ff、f_2、g_2、u、v、A、D、D'、B、B'、poly1、d'、b'、d、b_1、L、F、c、G、w、R、e、H、Q、poly3、r、q、h、g、E、t等对象。适合高中至大学阶段学习解析几何、射影几何或使用动态几何软件进行探究性教学,也可用于教师演示圆锥曲线与射影变换的直观联系。

GeoGebra 命令及参数

  1. Intersect(xAxis, yAxis) → E_1
  2. Mirror(F_1, yAxis) → G_1
  3. Mirror(FF, yAxis) → FF'
  4. Polygon(FF', FF, F_1, G_1) → poly5, ff', ff, f_2, g_2
  5. Mirror(D, A) → D'
  6. Mirror(B, A) → B'
  7. Polygon(D', B', D, B) → poly1, d', b', d, b_1
  8. PointIn(poly1) → L
  9. Midpoint(d) → F
  10. Segment(F, D) → c
  11. Point(c) → G
  12. Line(G, b') → e
  13. Intersect(e, d') → H
  14. Polygon(R, Q, H, G) → poly3, r, q, h, g
  15. Point(b') → E
  16. Segment(L, E) → t
  17. Intersect(t, e) → U
  18. Segment(E, O) → f
  19. Line(U, f) → c_1
  20. Point(f) → P
  21. Segment(P, L) → i
  22. Intersect(c_1, i) → V
  23. Line(V, q) → r_2
  24. Intersect(r_2, h) → B_2
  25. Segment(V, B_2) → t_2
  26. Mirror(H, D') → H'
  27. Midpoint(D', F) → I
  28. Midpoint(d') → J
  29. PointIn(poly1) → K
  30. PointIn(poly1) → M
  31. PointIn(poly1) → N
  32. Polygon(L, N, M, K) → poly2, l, n, m, k
  33. Segment(P, N) → j
  34. Segment(P, M) → p
  35. Segment(P, K) → s
  36. Segment(K, E) → a_1
  37. Intersect(a_1, e) → S
  38. Intersect(e, h) → T
  39. Line(S, f) → d_1
  40. Intersect(d_1, s) → W
  41. Segment(N, E) → e_1
  42. Segment(M, E) → f_1
  43. Intersect(e_1, e) → A_1
  44. Intersect(f_1, e) → B_1
  45. Line(A_1, f) → g_1
  46. Intersect(j, g_1) → C_1
  47. Line(B_1, f) → h_1
  48. Intersect(h_1, p) → D_1
  49. Polygon(V, C_1, D_1, W) → poly4, v_1, c_2, d_2, w_1
  50. Segment(P, E) → i_1
  51. Segment(D, E) → j_1
  52. Line(C_1, V) → l_1
  53. Intersect(l_1, r) → J_1
  54. Intersect(l_1, h) → K_1
  55. Segment(R, J_1) → m_1
  56. Segment(G, K_1) → n_1
  57. Line(D_1, W) → q_1
  58. Intersect(r, q_1) → L_1
  59. Intersect(h, n_1) → M_1
  60. Intersect(q_1, h) → N_1
  61. Segment(R, L_1) → r_1
  62. Line(V, W) → a_2
  63. Intersect(g, a_2) → O_1
  64. Line(C_1, D_1) → e_2
  65. Intersect(e_2, g) → P_1
  66. Intersect(l_1, q_1) → U_1
  67. Segment(N_1, U_1) → k_2
  68. Line(W, r) → k_1
  69. Line(W, g) → p_1
  70. Intersect(k_1, g) → I_1
  71. Intersect(p_1, h) → Q_1
  72. Segment(I_1, G) → t_1
  73. Segment(G, Q_1) → i_2
  74. Line(D_1, g) → s_1
  75. Line(D_1, r) → b_2
  76. Intersect(b_2, g) → R_1
  77. Intersect(h, poly1) → S_1, S_2
  78. Intersect(s_1, h) → T_1
  79. Segment(R_1, D_1) → h_2
  80. Segment(D_1, T_1) → j_2
  81. Line(WH, ff') → l_2
  82. Line(WL, g_2) → m_2
  83. Intersect(l_2, m_2) → V_1
  84. Line(DH, ff') → n_2
  85. Line(DL, g_2) → p_2
  86. Intersect(p_2, n_2) → W_1
  87. Line(V, r) → q_2
  88. Intersect(q_2, poly3) → Z_1, A_2
  89. Segment(V, A_2) → s_2
  90. Line(VD, g_2) → a_3
  91. Line(VH, ff') → b_3
  92. Intersect(a_3, b_3) → C_2
  93. Line(C_1, r) → c_3
  94. Line(C_1, g) → d_3
  95. Intersect(h, poly1) → D_2, D_3
  96. Intersect(h, poly1) → E_2, E_3
  97. Intersect(c_3, q) → F_2
  98. Intersect(h, poly1) → G_2, G_3
  99. Intersect(d_3, h) → H_2
  100. Segment(F_2, C_1) → e_3
  101. Segment(C_1, H_2) → f_3
  102. Line(CH, ff') → g_3
  103. Line(CL, g_2) → h_3
  104. Intersect(g_3, h_3) → I_2
  105. Polygon(C_2, V_1, W_1, I_2) → poly6, c_4, v_2, w_2, i_3
  106. PointIn(poly1) → L_2
  107. Conic(L_2, K, L, N, M) → k_3
  108. Segment(L_2, P) → j_3
  109. Segment(E, L_2) → l_3
  110. Intersect(l_3, poly1) → M_2, M_3
  111. Intersect(l_3, poly1) → N_2, N_3
  112. Intersect(e, l_3) → O_2
  113. Line(O_2, g) → m_3
  114. Intersect(m_3, j_3) → P_2
  115. Conic(W, V, C_1, D_1, P_2) → p_3
  116. Line(P_2, r) → n_3
  117. Line(P_2, g) → q_3
  118. Intersect(n_3, g) → Q_2
  119. Intersect(q_3, h) → R_2
  120. Segment(P_2, R_2) → r_3
  121. Segment(P_2, Q_2) → s_3
  122. Conic(ZH, V_1, C_2, I_2, W_1) → t_3
  123. Line(P, A) → f_4
  124. Point(f_4) → C
  125. Sphere(C - (0, 0.13, -0.05), 0.3) → o_1
  126. Sphere(C, 0.2) → u_1
  127. Sequence(R + (i * Vector[R, Q]), i, 0, 1, 1 / o_2) → l1
  128. Sequence(G + (i * Vector[R, Q]), i, 0, 1, 1 / o_2) → l2
  129. Sequence(G + (i * Vector[G, R]), i, 0, 1, 1 / u_2) → l3
  130. Sequence(H + (i * Vector[G, R]), i, 0, 1, 1 / u_2) → l4
  131. Sequence(Segment[Element[l3, i], Element[l4, i]], i, 1, Length[l3]) → l5
  132. Sequence(Segment[Element[l1, i], Element[l2, i]], i, 1, Length[l1]) → l6

AI 绘图提示语参考

绘制一个椭圆及其投影几何构造图。先画出坐标轴,以原点为中心,在纵轴两侧对称放置两个点,并连接它们构成一个四边形。再取另一组对称点构成第二个四边形,在其中任取一点,连接该点与四边形某边中点形成线段,并在该线段上取一点,过此点作直线与另一条边相交。继续构造多个交点与连线,形成一系列三角形和四边形。最后在四边形内部随机取多个点,连接它们与外部点,形成多条交叉线段,并标出所有交点。整体呈现复杂的几何网络,突出椭圆与投影变换的关系。
以上提示语为根据原始绘图命令整理而来,仅供参考。