Conchoid of Dürer

The conchoid by Dürer, or even shell line is a special plane algebraic curve. Albrecht Dürer drew for the first time in his book Underweysung of measurement ( p. 38), calling it " a muschellini ".

Equation

• Cartesian coordinates:

• Parameter equation (2 curve branches ):

( The second branch of the curve was not discovered by Dürer. )

Properties

• For degenerate the curve to the pair of straight lines and a circle.

• For the two curve branches degenerate to the straight line.

• For the curve has a peak at.