Freeth's Nephroid

A Strophoid of a Circle with the Pole at the Center of the Circle and the fixed point on the Circumference of the Circle. In a paper published by the London Mathematical Society in 1879, T. J. Freethdescribed it and various other MacTutor Archive). If the line through Parallelto the y-Axis cuts the Nephroid at , then Angle is , so this curve can be used toconstruct a regular Heptagon. The Polar equation is

References

Lawrence, J. D. A Catalog of Special Plane Curves. New York: Dover, pp. 175 and 177-178, 1972.

MacTutor History of Mathematics Archive. ``Freeth's Nephroid.''http://www-groups.dcs.st-and.ac.uk/~history/Curves/Freeths.html.

• Helicoid
• Helix
• Helly Number
• Helly's Theorem
• Helmholtz Differential Equation
• Helmholtz Differential Equation--Bipolar Coordinates
• Helmholtz Differential Equation--Cartesian Coordinates
• Helmholtz Differential Equation--Circular Cylindrical Coordinates
• Helmholtz Differential Equation--Confocal Ellipsoidal Coordinates
• Helmholtz Differential Equation--Confocal Paraboloidal Coordinates
• Helmholtz Differential Equation--Conical Coordinates
• Helmholtz Differential Equation--Elliptic Cylindrical Coordinates
• Helmholtz Differential Equation--Oblate Spheroidal Coordinates
• Helmholtz Differential Equation--Parabolic Coordinates
• Helmholtz Differential Equation--Parabolic Cylindrical Coordinates
• Helmholtz Differential Equation Polar Coordinates
• Helmholtz Differential Equation--Prolate Spheroidal Coordinates
• Helmholtz Differential Equation--Spherical Coordinates
• Helmholtz Differential Equation--Spherical Surface
• Helmholtz Differential Equation--Toroidal Coordinates
• Helmholtz's Theorem
• Helson-Szegö Measure
• Hemicylindrical Function
• Hemisphere
• Hemispherical Function