## witch of Agnesi

witch of Ag·ne·sinoun

A planar cubic curve that is symmetric about the

*y*-axis and that approaches the*x*-axis as an asymptote. Its equation is*x*^{2}*y*= 4*a*^{2}(2*a*−*y*), where*a*is a constant.Origin of witch of Agnesi

**witch**(translation of Italian

*avversiera, versiera*, confused with

*versiera*,

*curve, turning*, from New Latin

*vers&omacron;ria*, from Latin

*versus*,

*turned, reversed*, past participle of

*vertere*,

*to turn*; see

**verse**

^{1}) + Maria Gaetana

**Agnesi**.

**witch of Agnesi**

A segment drawn from the origin to A intersects a circle of radius a at B. The witch of Agnesi is the curve formed by P as A moves along the line C.