圆与切线的动画演示

GeoGebra 命令及参数

1. Circle(A, B) → c
2. Segment(A, B) → f
3. Segment(A, C) → g
4. Point(g) → D
5. Circle(D, C) → d
6. Point(d) → E
7. Line(D, E) → h
8. OrthogonalLine(E, h) → i
9. Line(C, E) → j
10. Intersect(c, j, 2) → F
11. Tangent(F, c) → k,
12. Segment(A, F) → l
13. Segment(D, E) → m
14. Circle(E, a) → e
15. Circle(F, a) → p
16. Intersect(p, k) → G, H
17. Intersect(e, i) → I, J
18. Intersect(p, l, 1) → K
19. Intersect(e, m, 1) → L
20. Angle(G, F, K) → α
21. Angle(J, E, L) → β
22. Intersect(e, j, 1) → M
23. Intersect(p, j, 1) → N
24. CircleSector(E, M, I) → q
25. Dilate(D, If[0 < b ≤ 1, 1 - b, 0], E) → D'
26. Segment(D, D') → n
27. Dilate(A, If[1 < b ≤ 2, 2 - b, 0], F) → A'
28. Segment(A, A') → r
29. Angle(M, E, I) → γ
30. Rotate(M, If[4 < b ≤ 5, ((b - 4) * γ), γ], E) → M'
31. CircleSector(E, M, M') → s
32. Dilate(E, If[5.5 < b ≤ 6.5, 6.5 - b, 0], F) → E'
33. Vector(E, E') → u
34. Dilate(C, If[2 < b ≤ 3, 3 - b, 0], E) → C'
35. Segment(C, C') → t
36. Dilate(E, If[3 < b ≤ 4, 4 - b, 0], F) → E'_1
37. Segment(E, E'_1) → f_1
38. Translate(q, u) → s'