# Witch Of Agnesi

**WITCH OF AGNESI**, in geometry, a. cubic curve invented by Maria Gaetana Agnesi. It is constructed by the following method: Let AQB be a
semicircle of diameter AB, produce MQ the ordinate of Q to P so that MQ : MP :: AM : AB. Then the locus of P is the witch. The cartesian equation, if A be taken
as origin and AB( = 2<z) for the axis of *, is xy* = 4d*(2a x). The curve consists of one branch entirely to the left of the line x=2a and having the axis of
y as an asymptote.

*Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)*