Augustin Louis Cauchy is a well-known French mathematician who accurately proved the theorems of the calculus of infinitesimals.

###### Childhood and early years

Augustin Louis Cauchy was the son of a high-ranking French municipal employee Louis-Francois Cauchy and his wife Marie-Madeleine Deszester.

Augustin had two brothers: Alexander Loren Cauchy and Juan François Cauchy.

During the French Revolution, Cauchy’s father loses his job, and the family moves to Arquei, where the boy receives his primary education.

But when the political situation in the country becomes calm, the Cauchy family returns to Paris.

Augustin is admitted to the city’s best middle school, the Pantheon’s Central School. During his studies the boy earns many awards for his achievements in the Latin language and the humanities.

After school, Cauchy decides to receive the profession of an engineer and passes the entrance exams to the faculty, gaining a mean score. From the Polytechnic School it is issued in 1807.

Then he enters the École des Ponts et Chaussées, which he graduates with a civil engineer diploma.

In the future, Cauchy is working on the construction project of the military port, but, despite all his employment, still finds time to prepare scientific notes on mathematics.

He will present his notes to the Main Section of the Institute of France.

In 1805, Cauchy found the solution of the Apollonius Problem.

###### Work experience

In November 1815, Cauchy undertook the teaching of mathematics to sophomores at the Polytechnic School.

A year later he was already becoming a professor at the school.

Since 1824, significant works of Cauchy on mathematics have been published.

And in the same period he receives offers to teach simultaneously at the College de France and the Faculty of Natural Sciences of the University of Paris.

In 1825, Cauchy formulated the “Theory of functions of a complex variable,” which is considered one of the key works in the field of mathematics.

In 1826, he introduced a clear definition of “deduction of function.”

Augustin-Louis Cauchy proves Taylor’s theorem and calculates the “remainder term” of the theorem.

In 1830, after the riots in Paris, Cauchy left his homeland and traveled to Switzerland, Sardinia and the Czech Republic.

In 1831 he proves the Cauchy Integral Theorem. In 1838 the scientist returned to Paris.

In 1839, Cauchy was appointed to the Bureau of Longitudes, founded in 1795 to determine the coordinates of geographical objects on the water surface of the Earth.

But, since the scientist refuses to bring a mandatory oath to the elected members, the king rejects his appointment.

Paying for his work in the Bureau of Cauchy does not receive, but, nevertheless, continues his studies and presents a number of papers on the topic “Celestial Mechanics”.

Later, in 1843, Cauchy replaced Poinsot in his position.

After leaving the Bureau, Cauchy is trying to get a place at the College de France, but there was no response to his proposal.

He teaches at the Middle Spiritual School, which prepares teachers for teaching.

An important role played by Cauchy in the founding of the Catholic Institute.

###### Basic work

Cauchy is the author of a number of important scientific works on mathematics: “The collection of works of Augustin Cauchy, published under the scientific supervision of the French Academy of Sciences and under the patronage of the Minister of Education” in 27 volumes, “An Analysis Tutorial for the Royal Polytechnic School,” etc.

###### Personal life and heritage

In 1818, Cauchy marries Alois de Bure, who came from a family of publishers and bookstore owners who published most of his work.

In the family of Augustin and Alois, two daughters were born: Marie Francoise Alicia and Marie Matilda Augustin.

Cauchy died on May 23, 1857.

No mathematician – with the possible exception of Leonard Euler – left behind so many scientific works as Augustine Cauchy.