Vectors: Parabola from Three Points (Focus and Directrix)

Classical Parabola construction from three points F, A, B. The parabola is all points equidistant from F and the line through A and B.

More: The same equation in 3-dimensional space: http://www.geogebratube.org/student/m32476 The second order Bezier Curve: http://www.geogebratube.org/material/show/id/37814 ToDo: Show the parabola defined as a conic section. A cone touches F and the line D = AB. Move the cone up and down, through the plane, holding F and D fixed. Let F and D draw on the cone. Probably easier in Blender.