动态圆与切线问题

GeoGebra 命令及参数

1. Circle(O, B_1) → c
2. Point(c) → A
3. Ray(A, O) → f
4. Intersect(c, f, 2) → G_1
5. Semicircle(G_1, A) → d
6. Point(d) → B
7. Segment(B, O) → g
8. Segment(O, A) → h
9. Angle(A, O, B) → α
10. Rotate(A, (0.5 * α), O) → C
11. Ray(O, C) → i
12. Line(B, A) → j
13. Intersect(j, i) → D
14. Circle(C, O) → e
15. Circle(A, C) → k
16. Line(A, O) → n
17. Circle(C, Segment[O, A]) → p
18. Circle(A, Segment[A, O]) → q
19. Intersect(p, q, 1) → E
20. Line(A, E) → l
21. Circle(E, Segment[A, D]) → r
22. Intersect(r, l, 2) → F
23. Line(F, C) → m
24. Intersect(n, m) → G
25. Line(E, G) → s
26. Intersect(s, i) → H
27. Circle(H, C) → t
28. Rotate(B, (π - α) / 2, O) → B'
29. Angle(B, O, B') → β
30. Ray(O, B') → a
31. Segment(B, G_1) → b
32. Intersect(a, b) → I
33. Circle(G_1, Segment[G_1, O]) → c_1
34. Circle(B, Segment[G_1, O]) → d_1
35. Circle(B, Segment[O, B]) → e_1
36. Circle(B', Segment[O, B]) → f_1
37. Intersect(e_1, f_1, 2) → J
38. Line(B, J) → g_1
39. Circle(J, Segment[B, I]) → h_1
40. Intersect(h_1, g_1, 2) → K
41. Ray(B, O) → i_1
42. Ray(K, B') → j_1
43. Intersect(i_1, j_1) → L
44. Ray(L, J) → k_1
45. Intersect(a, k_1) → M
46. Circle(M, B') → p_1
47. OrthogonalLine(M, n) → l_1
48. OrthogonalLine(H, n) → m_1
49. OrthogonalLine(M, g) → n_1
50. OrthogonalLine(H, g) → q_1
51. Intersect(l_1, n) → N
52. Intersect(m_1, n) → P
53. Intersect(g, q_1) → Q
54. Intersect(n_1, g) → R
55. Line(C, P) → r_1
56. Line(B, G_1) → s_1
57. Line(B', N) → t_1
58. Intersect(s_1, t_1) → S
59. Line(B, A) → a_1
60. Intersect(r_1, a_1) → T
61. Dilate(B, If[0 < v ≤ 1, 1 - v, 0], G_1) → B'_1
62. Segment(B, B'_1) → b_1
63. Dilate(B', If[1 < v ≤ 2, 2 - v, 0], S) → B''
64. Segment(B', B'') → f_2
65. Dilate(S, If[2 < v ≤ 3, 3 - v, 0], N) → S'
66. Segment(S, S') → g_2
67. Dilate(B, If[3 < v ≤ 4, 4 - v, 0], A) → B'_2
68. Segment(B, B'_2) → h_2
69. Dilate(C, If[4 < v ≤ 5, 5 - v, 0], T) → C'
70. Segment(C, C') → i_2
71. Dilate(T, If[5 < v ≤ 6, 6 - v, 0], P) → T'
72. Segment(T, T') → j_2
73. Dilate(S, If[7 < v ≤ 8, 8 - v, 0], R) → S'_1
74. Segment(S, S'_1) → k_2
75. Dilate(R, If[8 < v ≤ 9, 9 - v, 0], T) → R'
76. Segment(R, R') → l_2
77. Dilate(S, If[9 < v ≤ 10, 10 - v, 0], Q) → S'_2
78. Vector(S, S'_2) → w
79. Translate(S, w) → S'_3
80. Translate(S'_1, w) → U
81. Segment(S'_3, U) → m_2
82. Dilate(R, If[10 < v ≤ 11, 11 - v, 0], S) → R'_1
83. Vector(R, R'_1) → u_1
84. Translate(R, u_1) → R'_2
85. Translate(R', u_1) → R''
86. Segment(R'_2, R'') → n_2
87. Polygon(S, Q, T, R) → q1, s_2, q_2, t_2, r_2
88. Segment(G_1, A) → p_2