The pedal curve of the cissoid, when the pedal point is on the axis beyond the asymptote at a distance from the cusp which is four times that of the asymptote is a cardioid.

CITE THIS AS:

Weisstein, Eric W. "Cissoid of Diocles Pedal Curve." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/CissoidofDioclesPedalCurve.html