椭圆与圆的轨迹演示

椭圆与圆的轨迹演示
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2020-06-20 04:29
①本范例演示了通过两个圆的交点轨迹生成椭圆的过程;②涉及的核心数学概念包括圆、椭圆、轨迹、解析几何;③作图要点提炼自构造摘要,使用了Line(线段)、Circle(圆)、Intersect(交点)、Point(点)、Rotate(旋转)、Ray(射线)、Segment(线段)、CurveCartesian(笛卡尔曲线)、Polygon(多边形)、CircleArc(圆弧)等GeoGebra命令/对象;④适合高中及以上学生学习和理解椭圆的几何性质与参数方程。

GeoGebra 命令及参数

  1. Line(A, xAxis) → n
  2. Circle(A, R) → c
  3. Intersect(c, n) → E, F
  4. Point(c) → B
  5. Circle(A, R + r) → d
  6. Rotate(F, (t * w), A) → B'
  7. Ray(A, B') → a
  8. Intersect(d, a) → C,
  9. Circle(B', C) → e
  10. Rotate(C, (t * w1), B') → B''
  11. Ray(C, B'') → b
  12. Segment(C, B'') → i
  13. Segment(A, B') → j
  14. CurveCartesian(x(A) + ((R + r) * (cos((w * i)) + cos((w1 * i)))), y(A) + ((R + r) * (sin((w * i)) + sin((w1 * i)))), i, 0, t) → k
  15. Point(i) → D
  16. Intersect(e, j) → J, K
  17. Segment(A, K) → h
  18. Ray(A, B') → f
  19. Intersect(e, f) → H, I
  20. Rotate(I, (t * w1), B') → I'
  21. Segment(B', I') → g
  22. CurveCartesian(x(A) + (R * cos((w * i))) + (r * cos(((w1 + w - π / 2) * i))), y(A) + (R * sin((w * i))) + (r * sin(((w1 + w - π / 2) * i))), i, 0, t) → l
  23. CurveCartesian(x(A) + (R * cos((w * i))) - (r * cos(((w1 + w) * i) + π)), y(A) + (R * sin((w * i))) - (r * sin(((w1 + w) * i) + π)), i, 0, t) → o
  24. Circle(A, R + r) → r_1
  25. Point(r_1) → L
  26. Rotate(L, 120°, A) → L'
  27. Rotate(L, 240°, A) → L'_1
  28. Polygon(L'_1, L, L') → t1, l', l'_1, l_1
  29. CircleArc(L'_1, L, L') → s
  30. CircleArc(L, L', L'_1) → c_1
  31. CircleArc(L', L'_1, L) → d_1
  32. Point(c) → O
  33. Segment(O, A) → m
  34. Midpoint(O, A) → P
  35. Midpoint(g) → Q
  36. Segment(A, N) → f_1
  37. Segment(A, M) → g_1
  38. Circle(A, I') → e_1
  39. Circle(A, N) → h_1
  40. Circle(A, M) → k_1
  41. Midpoint(g_1) → S
  42. Midpoint(f_1) → T