Deltoid Involute
DeltoidInvolute
x = 1/3[2cost-cos(2t)]
(1)
y = 1/3[2sint-sin(2t)]
(2)
is a hypocycloid involute for n=3
x_i = 1/9[2cost-cos(2t)]
(3)
y_i = 1/9[2sint+sin(2t)],
(4)
which is another deltoid scaled by a factor (n-2)/n=1/3 and rotated 1/(2·3)=1/6 of a turn.
See also
Deltoid, Deltoid Evolute, InvoluteExplore with Wolfram|Alpha
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Cite this as:
Weisstein, Eric W. "Deltoid Involute." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/DeltoidInvolute.html