Graphing using a Cartesian Plane Vocabulary Cartesian Plane

Graphing using a Cartesian Plane

Vocabulary Cartesian Plane - named after the mathematician Rene Descartes (1596 - 1650), is a plane with a rectangular coordinate system that associates each point in the plane with a pair of numbers. l Famous for saying, “I think, therefore, I am. ” l

Coordinates - A unique ordered pair of numbers that identifies a point on the coordinate plane. The first number in the ordered pair identifies the position with regard to the x-axis while the second number identifies the position on the y-axis l Graph - A visual representation of data that displays the relationship among variables, usually cast along x and y axes. l Origin – the point (0, 0) - where the X axis and Y axis cross. l

Quadrants l There are 4 quadrants (big surprise) marked with Roman Numerals I, III, IV. l They are numbered Counter Clockwise starting with the upper right.

Quadrants Quadrant X (horizontal) Y (vertical) Example I Positive (3, 2) II Negative Positive (-4, 1) III Negative (-2, -1) IV Positive Negative (3, -7)

Plotting Points l (x, y) is how we write Coordinate Pairs. l X always comes first. Always! l When graphing, Go over, then up. l Remember, walk over to the ladder then climb. If you climb then go over…You FALL!

Plotting Points (2, 5, ) (-4, 7) (-5 -2) (6, -4)

Interactive Lesson Time! l Pick 2 numbers between 1 and 20. l Randomly make one, both or none of them negative. l Graph them here.