Rene Descartes

Rene Descartes was a French mathematician whose 1637 work La Geometrie founded what is now called analytic, or Cartesian, geometry, a method for describing geometric shapes and relationships using algebraic equations by fixing points in space with numerical coordinates, the Cartesian coordinate system that still bears his name. This fusion of algebra and geometry, previously treated as largely separate branches of mathematics, allowed geometric problems to be translated into algebraic ones and solved with algebraic methods, and it became a foundational tool that later mathematicians, including Isaac Newton and Gottfried Leibniz, built on directly in developing calculus. Descartes also introduced now-standard mathematical notational conventions, including using superscript numbers to denote exponents and using letters near the end of the alphabet, x, y and z, for unknown quantities. Although Descartes is remembered at least as widely for his work in philosophy, including his famous statement I think, therefore I am, and for laying groundwork in what became analytic philosophy and the mechanistic view of nature, his mathematical achievement of uniting algebra and geometry into a single coherent framework stands as one of the pivotal developments in the history of mathematics.