透视定理动态演示

GeoGebra 命令及参数

1. Line(A_1, A') → f
2. Line(A_1, C') → g
3. Line(A_1, B') → h
4. Point(g) → C
5. Point(g) → C'_1
6. Point(f) → A'_1
7. Point(f) → A
8. Point(h) → B
9. Point(h) → B'_1
10. Circle(A'_1, 1) → r
11. Circle(A, 1) → t
12. Dilate(A_1, If[0 < a ≤ 1, 1 - a, 0], A) → N
13. Dilate(A_1, If[0 < a ≤ 1, 1 - a, 0], A') → O
14. Segment(A_1, N) → b
15. Segment(A_1, O) → i_1
16. Dilate(A_1, If[1 < a ≤ 2, 2 - a, 0], B') → P
17. Dilate(A_1, If[1 < a ≤ 2, 2 - a, 0], B) → Q
18. Segment(A_1, P) → l_1
19. Segment(A_1, Q) → m_1
20. Dilate(A_1, If[2 < a ≤ 3, 3 - a, 0], C') → H
21. Dilate(A_1, If[2 < a ≤ 3, 3 - a, 0], C) → I
22. Segment(A_1, H) → c
23. Segment(A_1, I) → d
24. Line(A', B') → j
25. Line(B, A) → k
26. Intersect(j, k) → D
27. Line(C', B') → l
28. Line(B, C) → m
29. Intersect(l, m) → E
30. Line(C', A') → n
31. Line(A, C) → p
32. Intersect(n, p) → F
33. Polygon(A, C, B) → poly1, b_1, a_1, c_1
34. Polygon(A', B', C') → poly3, c', a', b'
35. Dilate(B, If[5 < a ≤ 6, 6 - a, 0], D) → B'_2
36. Segment(B, B'_2) → i
37. Dilate(A', If[5 < a ≤ 6, 6 - a, 0], D) → A''
38. Segment(A', A'') → q
39. Dilate(B, If[6 < a ≤ 7, 7 - a, 0], E) → B'_3
40. Dilate(C', If[6 < a ≤ 7, 7 - a, 0], E) → C''
41. Segment(B, B'_3) → s
42. Segment(C', C'') → e
43. Dilate(A, If[7 < a ≤ 8, 8 - a, 0], F) → A'_2
44. Dilate(C', If[7 < a ≤ 8, 8 - a, 0], F) → C''_1
45. Segment(C', C''_1) → f_1
46. Segment(A, A'_2) → g_1
47. Dilate(D, If[10 < a ≤ 11, 11 - a, 0], E) → D'
48. Dilate(E, If[11 < a ≤ 12, 12 - a, 0], F) → E'
49. Segment(D, D') → h_1
50. Segment(E, E') → j_1