抛物线的反射性质 by dthurston

GeoGebra 命令及参数

1. Intersect(x = h, y = k) → Vertex
2. Parabola(Focus, directrix) → c
3. Point(c) → Point
4. Tangent(Point, c) → a,
5. Ray(Point, Focus) → b
6. OrthogonalLine(Point, a) → d
7. Mirror(Point, d) → Point'
8. Mirror(Focus, d) → Focus'
9. Ray(Point', Focus') → b'
10. Point(a) → A
11. Point(b') → B
12. Point(a) → C
13. Angle(Focus, Point, A) → α
14. Angle(C, Point, B) → β
15. Angle(B, Point, A) → γ
16. Angle(C, Point, Focus) → δ
17. Line(Vertex, Focus) → e