# Rene Descartes Mathematician

René Descartes was born in La Haye, Touraine (France) in March of 1596 and died at Stockholm on February 11, 1650. René, the second of a family of two sons and one daughter, was sent to the Jesuit School at La Flêche at the early age of eight. Since he was of poor health he was permitted to lie in bed till late in the mornings, a custom which he always followed. When Pascal visited in 1647 he told him that the only way to do good work in mathematics and to preserve his health was never to allow anyone to make him get up in the morning before he felt like itOn leaving school in 1612 Descartes went to Paris to be introduced to the world of fashion. Through the medium of the Jesuits, he met Mydorge, and renewed his childhood friendship with Mersenne. Together they devoted two years, from 1615 1617, to the study of mathematics. During that time a man of position usually entered either the army or the church and so in 1617 Descartes joined the army of Prince Maurice of Orange, then at Breda. Walking through the streets one day in Breda he noticed a placard in Dutch which made him quite curious. He asked a stranger to translate it into either French or Latin. The stranger was Isaac Beeckman, the head of the Dutch College at Dort. He told Descartes he would do so only if he would answer it for him. The placard was a challenge to the world to solve a certain geometrical problem. Descartes worked it out within a few hours, and a close friendship had formed between the two.This unexpected test of his mathematical attainments made the unpleasant life of the army distasteful to him, but because of family influence and tradition he remained a soldier. He was persuaded at the commencement of the Thirty Years? War he was persuaded to volunteer under Count de Bucquoy in the Bavarian army. He continued all this time however, to occupy his leisure with mathematical studies. He would date the first ideas of his philosophy and of his analytical geometry according to three dreams which he experienced on the night of November 10, 1619, at Neuberg. He regarded this day as one which determined his whole future.

Descartes resigned his commission in the spring of 1621, and spent the next five years traveling and studying mathematics. He settled in Paris 1626 and during the first few years there spent his time constructing optical instruments. Although he took time off for these pursuits he was still convinced that someday find in philosophy the theory of the universe.

In 1628, the founder of the Oratorians, Cardinal de Berulle, met Descartes, and was very impressed. He urged him to devote his life to the examination of truth. Descartes agreed, at the height of his power moved to Holland. He lived there for twenty years, giving up all his time to philosophy and mathematics. Descartes spent the first four years, from 1629 to 1633, writing Le Monde, an attempt to give a physical theory of the universe. Realizing that its publication was likely to create hostility in the church, he abandoned it. He then devoted himself to composing a treatise on universal science; ?Discours de la méthode pour bien conduire sa raison et chercher la vérité dans les sciences,? and he accompanied it with three appendices entitled La Dioptrique, Les Météores, and La Géométrie. In 1641 he wrote ?Meditationes,? in which he explained at some length his views on philosophy. In 1644 he issued the Principia Philosophiae, which was devoted to physical science, especially the laws of motion and the theory of vortices. In 1647 he received a pension from the French court for his discoveries. Descartes went to Sweden on the invitation of the Queen in 1649, and died only a few months later of inflammation of the lungs.

Descartes wore many hats: he was a soldier, a teacher, a mathematician, and a philosopher. One could say that modern mathematics actually began with the work of Descartes. His invention of coordinate geometry paved the way for advances in mathematics. Descartes invented what we now call Cartesian coordinates, a system where we can graph mathematical functions in two-or three-dimensional space. Once Descartes had proved his own existence and God?s, he moved on to the sciences and demonstrated that math was the truest of all sciences. He actually ended up revolutionizing it and today math is based upon his Cartesian system. In Descartes system any curve is able to be addressed from an algebraic view. All math students learn this as the x and y plane. Any point can be written by its x position and its y position. All positions are measured relative to the x-axis and the y-axis respectively. From this basic idea came more complex ones. The equation of a line can be found with only two points, a point and the slope of the line, or by the slope and the point the line crosses the y-axis, know as the y intercept.

(Below is an illustration of the ?Cartesian coordinate system.?)

When one is working with equations (or inequalities) in two variables, it is useful to be able to show the values graphically. Descartes made this possible with this coordinate system made up of two number lines, one usually labeled the x-axis which runs horizontally, and the other usually labeled the y-axis, which runs vertically. These axes meet at the point the origin where they are both zero.

To identify points on a graph, we use the notation points(a,b) where a is the x-coordinate and b is the y-coordinate.

As an example, we would say the point in the graph at right is the point (2,3). We always specify the x-coordinate first, then the y-coordinate.

From his earliest scholastic achievements he was destined for greatness. He is known as the ?Father of Modern Mathematics? and the ?Father of Modern Rationalism.? His system of deductive reasoning has been adapted to almost every field of science. His major contributions to the field of math were the Cartesian coordinate system, the exponent, and the development of analytical geometry. Rene Descartes, although he died in his early 50?s, was a great mathematician and philosopher. Well disciplined in all genres, he will be remembered most for proving his own existence by the statement, ?I think, therefore I am.?

Rene Descartes Mathematician
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