Logarithmic Spiral Pedal Curve

Author

Eric W. Weisstein
March 16, 2008

This notebook downloaded from http://mathworld.wolfram.com/notebooks/PlaneCurves/LogarithmicSpiralPedalCurve.nb.

For more information, see Eric's MathWorld entry http://mathworld.wolfram.com/LogarithmicSpiralPedalCurve.html.

©2008 Wolfram Research, Inc. except for portions noted otherwise

Equation

logspiral={Cos[t]Exp[a t],Sin[t]Exp[a t]}

xy=PedalCurve[logspiral,{0,0},t]//Simplify

Simplify[Norm[xy],t∈Reals&&a>0]

Plot

PedalCurvePlot[logspiral /. a->1,{0,0},{t,-2,50},{0,2,.3},PlotRange->{{-2,5},{-1,9}},AxesOrigin->{0,0}]