Parabola: Vertex and (Focus or Point on arc)
- Author:
- Ryan Hirst
- Topic:
- Parabola
I take V as the origin of local coordinates . F must then lie on the line through x2. P is a free point in space.
One point controls one property:
Translation (Vertex V),
Rotation (A),
Scale/Shape* (F or P).
If F is moved, P is not uniquely determined. I choose to hold k constant, and vary h. In words, F changes the width of the parabola.
Now, F and P have the same job. This is a good time to introduce a control structure: