Eccentricity, Directrix & Focus

Explore!

Use the applet below to animate the construction of a parabola as the locus of points equidistant to a point (Focus) and line (Directrix). 

The ratio of the distances is known as the eccentricity, as the eccentricity, observe the shape of the conics formed when c < 1 (Ellipse) versus c > 1 (Hyperbola).