Did you know . .
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The man who invented analytic geometry, René Descartes (1596-1650), never got out of bed before 11 in the morning!

Analytic geometry brings together the
analytical tools of algebra and the visual immediacy of geometry
by providing a way to visualize algebraic
functions. Descartes, a French philosopher and mathematician,
did this through the introduction of the coordinate
system that still bears his name, the Cartesian coordinate
system. Descartes published his ideas in 1637 in a treatise called
*La géométrie *(*Geometry*)*.*

It is said (although the story is probably a myth) that Descartes came up with the idea for his coordinate system while lying in bed and watching a fly crawl on the ceiling of his room.

**René Descartes.**

(Source: http://www.ga.k12.pa.us/academics/US/Math/Millar/Descartes/Burka.htm)

Descartes' *Geometry* was
an appendix to a larger work called *Discourse
on the Method of Properly Conducting One's Reason and of Seeking
the Truth in the Sciences*. In this work, Descartes set
out to place human knowledge on a new, firm footing, an important
task in an age beset with doubts and controversy and in which
skepticism reigned. Descartes himself had seen service in warfare
spurred by religious disagreements, and he was no stranger to
scientific controversy, either. In 1633, hearing that Galileo
had been condemned for teaching that the earth moved around the
sun, Descartes abruptly decided not to publish a work defending
the idea of a sun-centered univierse.

Descartes found a model for
proper reasoning in mathematics, especially in geometry, and his
appendix on *Geometry* was meant to illustrate the effectiveness
and usefulness of his method. His method was based on four
basic rules for deducing knowledge in the manner of a geometry
proof. His famous line, "I think, therefore I am," reveals
the first firm piece of knowledge upon which his subsequent deductions
were based.

In 1649, Descartes accepted an invitation from Queen Christine of Sweden to move to the Swedish court in Stokhlom and become her private tutor. His new employer, however, forced him to begin lessons at 5 a.m.! For a man who had stayed in bed till 11 since childhood, this early rising, combined with the cold climate, proved to be too much. He died of a lung inflammation on February 11, 1650.

I thought the following four [rules]
would be enough, provided that I made a firm and constant resolution
not to fail even once in the observance of them. The first was
never to accept anything as true if I had not evident knowledge
of its being so; that is, carefully to avoid precipitancy and
prejudice, and to embrace in my judgment only what presented itself
to my mind so clearly and distinctly that I had no occasion to
doubt it. The second, to divide each problem I examined into as
many parts as was feasible, and as was requisite for its better
solution. The third, to direct my thoughts in an orderly way;
beginning with the simplest objects, those most apt to be known,
and ascending little by little, in steps as it were, to the knowledge
of the most complex; and establishing an order in thought even
when the objects had no natural priority one to another. And the
last, to make throughout such complete enumerations and such general
surveys that I might be sure of leaving nothing out. These long
chains of perfectly simple and easy reasonings by means of which
geometers are accustomed to carry out their most difficult demonstrations
had led me to fancy that everything that can fall under human
knowledge forms a similar sequence; and that so long as we avoid
accepting as true what is not so, and always preserve the right
order of deduction of one thing from another, there can be nothing
too remote to be reached in the end, or to well hidden to be discovered.

*Discours de la Méthode*. 1637.

*Omnia apud me mathematica fiunt*.

With me everything turns into mathematics.

*Cogito ergo sum*. "I think, therefore I am."

*Discours de la Méthode*. 1637.

It is not enough to have a good mind. The main thing is to
use it well.

*Discours de la Méthode*. 1637.

If you would be a real seeker after truth, you must at least
once in your life doubt, as far as possible, all things.

*Discours de la Méthode*. 1637.

(Source: http://www-groups.dcs.st-andrews.ac.uk/~history/Quotations/Descartes.html)

*Fun links:*

Page with dynamic applets for graphing on the Cartesian and other coordinate systems: http://www.univie.ac.at/future.media/moe/galerie/zeich/zeich.html

Application to convert between Cartesian and polar coordinates: http://qmc.yi.org/mrtutor/math/CoordScript.html

Graph sketcher application for sketching functions on the Cartesian coordinate system (Be sure to click the "How?" button for insturctions on how to type in mathematical symbols!): http://www.shodor.org/interactivate/activities/sketcher/index.html

Maze game using the Cartesian coordinate system: http://www.shodor.org/interactivate/activities/coords/index.html

*For more information:*

http://www-groups.dcs.st-andrews.ac.uk/~history/Mathematicians/Descartes.html

http://www.maths.tcd.ie/pub/HistMath/People/Descartes/RouseBall/RB_Descartes.html

http://es.rice.edu/ES/humsoc/Galileo/Catalog/Files/descarts.html

http://www.newadvent.org/cathen/04744b.htm

http://library.thinkquest.org/22584/temh3010.htm

http://www.britannica.com/eb/article?idxref=535632

By Laura Smoller, UALR Department of History.

March 2001.