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Monday, March 28, 2016

Rene Descartes

                As my regular readers know, I am taking a math class.   My latest lessons involve the Cartesian coordinate system – the standard coordinate system used in math.  I decided to learn a little about Mr. Descartes and discovered there is too much for me to learn about this man in one evening.  I decided to concentrate on his advances in math.

                Rene Descartes was born on March 31, 1596, in La Haye en Touraine, Kingdom of France.  His parents were Joachim Descartes and Jeanne Brochard.  His mother died in childbirth when he was one year old.  His father was a member of the Parlement of Brittany at Rennes; therefore Descartes lived with his grandmother and great-uncle.  He came from a Roman Catholic family that lived in an area controlled by Protestant Huguenots.  “In 1607, late because of his fragile health, he entered the Jesuit College Royal Henry-Le-Grand at La Fleche where he was introduced to mathematics and physics, including Galileo’s work.  After graduation in 1614, he studied two years (1615-16) at the University of Poitiers, earning a Baccalaureat and Licence in Canon and Civil Law, in accordance with his father’s wishes that he should become a lawyer….”

                Descartes became a French philosopher, mathematician, and scientist.  Even though he was “dubbed the father of modern western philosophy” he could be better known for his mathematical and scientific accomplishments.

                “One of Descartes’ most enduring legacies was his development of Cartesian or analytic geometry, which uses algebra to describe geometry.  He `invented the convention of representing unknowns in equations by x, y, and z, and knowns by a, b, and c’.  He also `pioneered the standard notation’ that uses superscripts to show the powers or exponents; for example, the 4 used in x4 to indicate squaring of squaring.  He was first to assign a fundamental place for algebra in our system of knowledge, and believed that algebra was a method to automate or mechanize reasoning, particularly about abstract, unknown quantities….

                “Descartes’ work provided the basis for the calculus developed by Newton and Gottfried Leibniz, who applied infinitesimal calculus to the tangent line problem, thus permitted the evolution of that branch of modern mathematics.  His rule of signs is also a commonly used method to determine the number of positive and negative roots of a polynomial….

                “Current opinion is that Descartes had the most influence of anyone on the young Newton, and this is arguably one of Descartes’ most important contributions.  Newton continued Descartes’ work on cubic equations, which freed the subject from the fetters of the Greek and Macedonian perspectives.  The most important concept was his very modern treatment of independent variables….”

                Descartes must have been a brilliant man because he made advances in numerous areas.  I wrote about his math prowess simply because I am just now learning about his Cartesian coordinate system.  He died on February 11, 1650, at age 53, in Stockholm, Sweden.  I saw no evidence of a wife or children.

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