You can
- Click and drag the foci, or
- Click and drag around the oval, or
- Select one of three types of curves:
- Ellipses, where the sum of distances from the two foci is constant
(here, it's 2);
- Ovals of Descartes, where the distance from the left focus
plus a multiple p of the distance to the right focus is a constant
(here, 1+p);
- Ovals of Cassini, where the product of distances to the foci
is a constant p.
When you drag in the area around the oval, the lengths of the two segments
are shown at upper left, and their sum (or weighted sum, or product)
appears below them, colored in red if you're on (or outside) the oval.
Written Oct 1997 by Stuart Levy
(slevy@ncsa.uiuc.edu),
NCSA, University of Illinois, Urbana-Champaign, for the
ChickScope project.
If you'd like to install this applet as part of another page, or to customize
it, please see the source and installation instructions.