抛物线快速解剖探索：焦点、准线与几何性质

GeoGebra 命令及参数

1. Point(Segment[(h, y(C) + 10), (h, y(C) - 10)]) → D
2. Line(A, B) → f
3. Vector(A, C) → u
4. Polygon(A, C, B) → t1, b, a_1, c
5. RotateText(text2, pi / 2) → text3
6. Segment(A, C) → h_{1}
7. Vector(C, D) → v
8. Vector((h, 0), A) → w
9. Vector((0, 0), (h, 0)) → j
10. Point(Segment[(x(C) - 10, k), (x(C) + 10, k)]) → E
11. Vector(A, E) → p
12. Point(eq1) → F
13. OrthogonalLine(F, q) → r
14. Intersect(q, r) → G
15. Point(q) → H
16. Angle(H, G, F) → α
17. Dilate(D, If[0 < s ≤ 1, 1 - s, 0], F) → D'
18. Segment(D, D') → t
19. Angle(G, F, D) → β
20. Rotate(D, If[1.5 < s ≤ 2.5, ((-(s - 1.5)) * β), (-β)], F) → D'_{1}
21. Rotate(D', If[1.5 < s ≤ 2.5, ((-(s - 1.5)) * β), (-β)], F) → D''
22. Segment(D'_{1}, D'') → t'
23. Point(eq2) → I
24. Dilate(E, If[0 < s ≤ 1, 1 - s, 0], I) → E'
25. Segment(E, E') → f_1
26. OrthogonalLine(I, eq3) → g_1
27. Intersect(g_1, eq3) → J
28. Point(eq3) → K
29. Angle(K, J, I) → γ
30. Angle(J, I, E) → δ
31. Rotate(E, If[1.5 < s ≤ 2.5, ((-(s - 1.5)) * δ), (-δ)], I) → E'_{1}
32. Rotate(E', If[1.5 < s ≤ 2.5, ((-(s - 1.5)) * δ), (-δ)], I) → E''
33. Segment(E'_{1}, E'') → i_1