椭圆术语 by Norm Prokup

GeoGebra 命令及参数

1. Ray(A, C) → j
2. Point(j) → D
3. Rotate(D, -90°, A) → D'
4. Ray(A, D) → h
5. Ray(D', H) → f
6. Point(f) → F
7. If(x(F) ≥ y(D), true, false) → isHorizontal
8. Min(x(F), y(D)) → b
9. Max(x(F), y(D)) → a
10. If(isHorizontal, (c, 0), (0, (-c))) → F_2
11. Ellipse(F_1, F_2, D) → d
12. Segment(E, F) → g
13. Segment(D, G) → i
14. Point(d) → P
15. Segment(F_1, P) → l
16. Segment(F_2, P) → m
17. Vector(K, I) → u
18. Vector(K, J) → v
19. Vector(N, L) → w
20. Vector(N, M) → e
21. Ray(A, P) → k
22. Circle(A, Distance[A, P] + 0.75) → p
23. Intersect(p, k, 1) → O
24. Vector(Q_2, T_2) → n
25. Vector(Q_2, U_2) → q
26. Vector(Q_1, T_1) → r
27. Vector(Q_1, U_1) → s