focus and directrix
- Esther Gruenhut
Given point F (=focus), and line (=directrix). Q is a point equidistant from the point and the line. Try moving Q
Let , and . How does changing the parameter affect the parabola?
And how about other points in the plane? In the applet below, move around point P, and try to notice: which points are closer to the focus, and which to the directrix?