抛物线几何性质演示

GeoGebra 命令及参数

1. Line(A, B) → a
2. Parabola(C, a) → c
3. OrthogonalLine(C, a) → b
4. Point(c) → D
5. Tangent(D, c) → d,
6. Intersect(b, d) → E
7. Intersect(a, b) → F
8. Distance(E, F) → e
9. Circle(D, (0.8 * e)) → g
10. Segment(C, D) → h
11. Intersect(g, d) → I, J
12. Intersect(g, h, 1) → K
13. CircleSector(D, K, J) → k
14. Dilate(C, If[-0.5 < i ≤ 0.5, 0.5 - i, 0], D) → C'
15. Segment(C, C') → j
16. Dilate(D, If[1 < i ≤ 2, 2 - i, 0], E) → D'
17. Vector(D, D') → u
18. Translate(k, u) → k'
19. Vector(D, E) → v
20. Translate(K, v) → K'
21. Translate(I, v) → I'
22. Angle(I', E, K') → α
23. CircleArc(D, K, J) → f
24. Rotate(k', If[2 < i ≤ 3, ((-(i - 2)) * α), (-α)], E) → k''
25. Intersect(b, a) → G
26. Circle(G, 0.1) → p
27. Intersect(p, a, 2) → H
28. Intersect(p, b, 2) → L
29. Angle(H, G, L) → β