Applet lets you look at level curves of a general quadratic
equation
It was created by Marc Renault
Mike May, S.J., February 27,
2009, Created with GeoGebra
This applet is a minor modification of one created by
Marc Renault
Mathematics Department, Shippensburg University
msrenault at ship dot edu
http://webspace.ship.edu/msrenault/
Used with permission