RENE DESCARTES

FAVORITE QUOTE:

WHO?

• René Descartes was born on March 31, 1596, in La Haye, France, and died on February 11, 1650, in Stockholm, Sweden.
• He was the youngest of three children, and his mother died when he was one.
• His father sent him to a boarding school at Jesuit College of Henri IV at age 8.
• Descartes is mostly known for his famous quote: "I think, therefore I am."
• He was a French philosopher, Scientist, and a Mathematician.

WHAT?

• His works were created from his idea "Cogito, ergo sum.", which means, "I think, therefore I am."
• In 1618, he was a student of mathematics and military architecture.
• He was influenced by physicist Isaac Beeckman in his studies of mathematics and science.
• He created a method of deductive reasoning for all sciences based on mathematics.

WHEN?

• Life span- March,1596-February,1650.
• Early education started at Jesuit College of Henri IV at age 8 thru 15.
• Age 15 thru 22 studied Law at the University of Poiters.
• Age 22, after graduating from the University of Poiters, he had visions that
• -determined the course of his study for the rest of his life.

WHEN?

• 1616-1629 Early mathematical researches
• 1628 Moved to the Netherlands.
• 1635 Daughter Francine was born. She died 5 years later from a fever.
• 1637 Wrote "La Géométrie"

WHERE?

• La Haye, Touraine, France - birthplace
• Stockholm, Sweden - residence at time of death
• Chatellerault and Poiters - location of Father's farms and houses
• Le Flèche, France - Studies
• Northern & Southern Europe - travelled 1619 to 1628

WHERE?

• Bohemia, Czech Republic - invented "analytic geometry" -1619
• Paris, France - moved here in 1622
• Netherlands - spent last 22 years of his life here after leaving Paris.

WHY?

• Great influence in his study of mathematics was Isaac Beeckman
• Beeckman engaged Descartes in thinking of the problems between
• -"falling bodies, physic-Mathematica and mathematical problems.
• Discovered theories and ideas during his studies with Beeckman that would
• -make analytic geometry possible.

WHY?

• He felt that geometry was the basic mathematical science
• -with algebraic formulas as an option for calculations that were too difficult
• -using a compass and ruler.
• Nineteenth century algebraic geometry became "Cartesian coordinates"; in honor of his
• -discovery.

HOW?

• Descartes explains "how" in his introduction in La Géométrie:
• "Any problem in geometry can be easily reduced to such terms that a
• -knowledge of the length of certain straight lines is sufficient for construction."
• Defined a unit of length and created procedures for adding, subtracting, multiplying and
• -dividing line segments and for graphically figuring out root segments.

HOW?

• Geometric problems could be expressed in algebraic terms
• --using a vertical axis, "a" and a horizontal axis, "b"
• Told Beeckman that there is no problem in geometry can't be expressed using
• -axis, lines and curves; such as lower a,b,c for known quantities and x,y,z
• --and lowercase x,y, and z for unknown quantities