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BIAXIAL INVERSE OF AN EIGHT


Homemade name.

 
Cartesian parametrization:  (), or  .

Cartesian equation:  or .
Rational quartic.
Rational Cartesian parametrization:  ().
Polar equation: .


 
As indicated by its name, the biaxial inverse of an eight is the image by the biaxial inversion  of the eight curve :.
We can easily see on the figure the tangents at the inflexion points and at the vertices of the eight, which are invariant under inversion and become the asymptotes of the inverse.

Compare to the cross curve, which is the biaxial inverse of a circle.
 
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© Robert FERRÉOL 2017