Bifolium

{{Short description|Quartic plane curve}}

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File:Bifolium01.svg

A bifolium is a quartic plane curve with equation in Cartesian coordinates:

:(x^2 + y^2)^2 = ax^2y.

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Construction and equations

File:Bifolium.gif

Given a circle C through a point O, and line L tangent to the circle at point O: for each point Q on C, define the point P such that PQ is parallel to the tangent line L, and PQ = OQ. The collection of points P forms the bifolium.{{Cite web |last=Kokoska |first=Stephen |date= |title=Fifty Famous Curves, Lots of Calculus Questions, And a Few Answers |url=https://facstaff.bloomu.edu/skokoska/curves.pdf |access-date=6 January 2018 |website=facstaff.bloomu.edu |publisher=}}

In polar coordinates, the bifolium's equation is

:\rho=a\sin\theta\cdot\cos^2\theta,

:while (first eqn.)

:\rho^{2\cdot2}=a\cdot x^2y,\,\,\rho^2=\pm x\cdot(ay)^{1/2}.

For a = 1, the total included area is approximately 0.10.

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See also

Reference

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