# Blaise Pascal

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Blaise Pascal was a 17th century French mathematician, philosopher, scientist, and writer. He was one of the most significant mathematicians of his time. He was born on June 19, 1623, and died on August 19, 1662, at the age of only 39. His father, Etienne, was a mathematician of note; the "limaçon of Pascal" is named after him. Blaise was a child prodigy, having written a significant paper about projective geometry when he was only sixteen years old.

Pascal's interests were varied. In 1641, he began building and selling calculating machines. In 1648 he became interested in hydrostatics and undertook a now-famous experiment showing that air had weight.

Some of Pascal's best-known contributions to mathematics were made in 1653 and 1654. During that period, a friend, the Chevalier de Méré raised questions similar to the following:

A man has placed a bet that, in eight throws of a die, he will throw a one. After three unsuccessful throws, the game is abandoned. How should the stakes be split?

Pascal corresponded with Fermat about questions such as the following, and their correspondence was the start of modern probability theory. Also in 1653, Pascal had come up with the idea of Pascal's triangle (although the idea was not original to him), deduced many important properties of Pascal's triangle, and related it to probability theory. Also in 1654, Pascal wrote a work on conics, no longer extant, although we have some idea of its contents based on Leibniz's notes about the work.

In late 1654, Pascal abandoned his scientific and mathematical work for theology. During this period in his life he wrote his most famous philosophical work, the Penseés. He only returned to mathematical work at one point in 1658–1659, when he wrote a few geometrical works. In Traité des sinus du quart de cercle he came close to achieving the ideas behind calculus, and Leibniz would later write that this work was an inspiration for him. Unfortunately, Pascal did not ever return to the study of mathematics, and died only a few years after writing that work, before his 40th birthday.