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.
witch of Ag·ne·si
(än-yā′zē)n.
A planar cubic curve that is symmetric about the y-axis and that approaches the x-axis as an asymptote. Its equation is x2y = 4a2(2a - y), where a is a constant.
[witch (translation of Italian avversiera, versiera, confused with versiera, curve, turning, from New Latin versōria, from Latin versus, turned, reversed, past participle of vertere, to turn; see verse1) + Maria Gaetana Agnesi.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
witch of Agnesi
(ɑːnˈjeɪzɪ)n
(Mathematics) maths a plane curve, symmetrical about the y-axis, having the equation x2y = 4a2(2a–y). Sometimes shortened to: witch
[C19: named after Maria Gaetana Agnesi (1718–99), Italian mathematician and philosopher; probably so called from the resemblance of the curve to the outline of a witch's hat]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014