In mathematics, particularly geometry, Viviani's curve, also known as Viviani's window, is a figure eight shaped space curve named after the Italian mathematician Vincenzo Viviani, the intersection of a sphere with a cylinder that is tangent to the sphere and passes through the center of the sphere.
The curve can be obtained by intersecting a sphere of radius centered at the origin,
with the cylinder centered at of radius given by
The resulting curve of intersection, , can be parameterized by to give the parametric equation of Viviani's curve:
This is a clelie with , where .
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