抛物线的焦点与准线

GeoGebra 命令及参数

1. Line(C, V) → a
2. Mirror(P, a) → P'
3. Segment(P, P') → f
4. Intersect(a, f) → A
5. CircleArc(V, A, C) → c
6. Intersect(c, a) → D, E
7. Segment(E, P) → t_P
8. Segment(E, P') → t_P'
9. OrthogonalLine(V, a) → t_v
10. Intersect(t_P, t_v) → F_1
11. OrthogonalLine(F_1, t_P) → g
12. Intersect(a, g) → F
13. Segment(F_1, F) → h
14. Angle(P, F_1, F) → α
15. CircleArc(V, F, C) → d_1
16. Intersect(d_1, a, 2) → B
17. OrthogonalLine(B, a) → d
18. Parabola(F, d) → e
19. Mirror(V, F_1) → T_P
20. Intersect(g, d) → D_P
21. Segment(D_P, P) → i
22. Segment(D_P, F_1) → j