Cartesian Coordinate System

Notes by:

Mrs. Lorraine Gordon

8th grade math instructor

History• Cartesian means relating to the French mathematician and

philosopher René Descartes, who, among other things, worked to merge algebra and Euclidean geometry. This work was influential in the development of analytic geometry, calculus, and cartography.

• The idea of this system was developed in 1637 in two writings by Descartes. In part two of his Discourse on Method he introduces the new idea of specifying the position of a point or object on a surface, using two intersecting axes as measuring guides. In La Géométrie, he further explores the above-mentioned concepts.

• See coordinates (mathematics) for other commonly used coordinate systems such as polar coordinates and coordinate systems for usage of the term in advanced mathematics.(wikipedia http://en.wikipedia.org/wiki/Cartesian_coordinate_system)

Cartesian Coordinate System

• The Cartesian Coordinate system is made up of:

• y axis runs up and down through the center

• X axis runs left to right through the center

• Origin which is where the x and y axis cross. The coordinates for the origin are (0,0)

Quadrants

• There are 4 quadrants or sections that are formed by the x and y axis crossing.

• The first number in an ordered pair tells you to move right or left from the origin. The second number tells you to move up or down from there.

Ordered Pairs

• (+,+) tells us move right and up

• (-,+) tells us to move left and then up

• (-,-) tells us to move left and then down

• (+,-) tells us to move right and then down

Ordered Pairs

• Look at the ordered pairs on the picture.

• You must start at the origin and go right or left first and then from there you must go up or down.

• (2,1) tells us to go to the right two lines along the x axis and then up 1.

• (-3,-2) tells us to go to the left 3 from the origin and then from there go down 2.