# The Witch Maria Gaetana Agnesi

Published by Gerald Ferreira Date: May 15, 2014

Categories:

## Maria Gaetana Agnesi Google Doodle

Google in Australia, New Zealand, Japan, Philippines, Indonesia, Oman, Iraq, Kenya, Egypt, Libya, Algeria, South Africa, Ukraine, Poland, Spain, Germany, Island, Italy, Brazil and the United Kingdom is today celebrating the life and legacy of Maria Gaetana Agnesi.

Maria Gaetana Agnesi was born on the 16^{th} of May 1718 in Milan, Italy and died on the 9^{th} of January 1799 in Milan at the age of 80. Maria Gaetana Agnesi is credited with writing the first book that discussed both differential mathematics and integral calculus mathematics. Her field of specialty was in Mathematics therefore the mathematics in the Google. To be more specific Maria Gaetana Agnesi is best known from the curve called the "Witch of Agnesi"

## Witch of Agnesi

Agnesi wrote the equation of this curve in the form y = a*sqrt(a*x-x*x)/x because she considered the x-axis to be the vertical axis and the y-axis to be the horizontal axis [Kennedy]. Reference frames today use x horizontal and y vertical, so the modern form of the curve is given by the Cartesian equation yx2=a2(a-y) or y = a3/(x2 + a2). It is a versed sine curve, originally studied by Fermat. "It was called a versiera, a word derived from the Latin vertere, meaning 'to turn', but it was also an abbreviation for the Italian word avversiera, meaning 'the wife of the devil'". However, when Maria's text was translated into English the word versiera was confused with "witch", and the curve came to be known as the witch of Agnesi.

## Maria Gaetana Agnesi the Brilliant Philosopher

Agnesi was the eldest child of a wealthy silk merchant who provided her with the best tutors available. She was an extremely precocious child who mastered Latin, Greek, Hebrew, and several modern languages at an early age, and her father liked to host gatherings where she could display her knowledge. Propositiones philosophicae (“Propositions of Philosophy”), a series of essays on natural philosophy and history based on her discussions before such gatherings, was published in 1738.

In 1750, on the illness of her father, she was appointed by Pope Benedict XIV to the chair of mathematics and natural philosophy and physics at Bologna, though she never served. She was the second woman ever to be granted professorship at a university, Laura Bassi being the first.