内切圆、外接圆与奈格尔点

GeoGebra 命令及参数

1. Line(A, B) → f
2. Line(B, C) → g
3. Line(C, A) → h
4. AngularBisector(f, h) → i, j
5. AngularBisector(f, g) → k, l
6. AngularBisector(h, g) → m, n
7. Intersect(i, k) → E_C
8. Intersect(j, l) → I
9. Intersect(i, l) → E_B
10. Intersect(j, k) → E_A
11. OrthogonalLine(E_C, f) → p
12. OrthogonalLine(I, f) → q
13. OrthogonalLine(E_A, f) → r
14. OrthogonalLine(E_B, f) → s
15. Intersect(f, s) → H
16. Intersect(f, p) → C'
17. Intersect(f, q) → J
18. Intersect(f, r) → K
19. OrthogonalLine(E_C, h) → t
20. OrthogonalLine(I, h) → a
21. OrthogonalLine(E_B, h) → b
22. OrthogonalLine(E_A, h) → c
23. Intersect(h, t) → L
24. Intersect(h, a) → M
25. Intersect(h, b) → B'
26. Intersect(h, c) → O
27. OrthogonalLine(E_C, g) → d
28. OrthogonalLine(I, g) → e
29. OrthogonalLine(E_A, g) → f_1
30. OrthogonalLine(E_B, g) → g_1
31. Intersect(g, d) → P
32. Intersect(g, e) → Q
33. Intersect(g, f_1) → A'
34. Intersect(g, g_1) → S
35. Circle(E_C, L) → c_1
36. Circle(E_B, B') → d_1
37. Circle(I, M) → e_1
38. Circle(E_A, O) → h_1
39. Polygon(A, B, C) → t1, c_2, a_1, b_1
40. Line(L, B) → i_1
41. Line(P, A) → j_1
42. Line(C, C') → k_1
43. Line(A, S) → l_1
44. Line(C, H) → m_1
45. Line(B, B') → n_1
46. Intersect(i_1, j_1) → N_C
47. Intersect(l_1, m_1) → N_B
48. Line(B, O) → p_1
49. Line(C, K) → q_1
50. Line(A, A') → r_1
51. Intersect(p_1, q_1) → N_A
52. Intersect(k_1, n_1) → N_a