'- - File: Evolute1.txt
pi = 3.14159
R<t> = <2cos[t], sin[t], 0>                       ' Position vector to find the Evolute.
T<t> = vTan[R]                                         ' The tangent

Ke{t} = sMag[vDiv[vDiff[T],sMag[vDiff[R]] ]]    ' ke{t} = |dT/dt| / (ds/dt) =  dT/ds
Ea<t> = vAdd[R, vDiv[Ke, vNorm[R]] ]            ' Evolute = R<t> + N<t> / Ke{t}

to = -pi  :  tf = pi  :  n = 100
Plot[R, Ea, {t, to, tf, n}]




