Tag Archives: Agnesi

Maria Gaetana Agnesi’s Doodle

Maria Gaetana Agnesi (Milan, 16 May, 1718 – 9 January, 1799) was born in a rich Italian family. She was a very clever girl who spoke Italian and French at five years of age and six years later she was able to speak Latin, Greek, Hebrew, German and Spanish. His father was mathematics teachers in the University of Bologna and he never stopped his daughter’s brightness so she wrote a very long speech about women’s rights to be educated when was only 9 y.o. She was always studing and she was very ill one year later because her great interest in all the sciences and humanistic subjects.

She studied Geometry and therefore her father invited her to his meetings with the most learned men in Bologna. Familiar problems let her to retire to study Mathematics and she could learn differential calculus. She became teacher at the university of Bologna and wrote the Instituzioni analitiche ad uso della gioventù italiana (Milan, 1748) where she show a great and didactic introduction to the differential and integral calculus and to the Euler’s works.

The doodle commemorates 296 years since her birthday and we can see the famous Witch of Agnesi. Quoting Wikipedia:

Starting with a fixed circle, a point O on the circle is chosen. For any other point A on the circle, the secant line OA is drawn. The point M is diametrically opposite to O. The line OA intersects the tangent of M at the point N. The line parallel to OM through N, and the line perpendicular to OM through A intersect at P. As the point A is varied, the path of P is the witch.

The curve is asymptotic to the line tangent to the fixed circle through the point O.

The Witch was studied by Pierre de Fermat in 1630 and by Guido Grandi in 1703 and Agnesi called it as “versiera” which is Grandi’s name.