Table of Contents
The Cartesian Plane
In the 17th century French mathematician, René Descartes, while in bed because of an illness, was watching a spider on the ceiling. As he watched, he thought of how he might describe the position of the spider at any instant. The technique he designed is called the Cartesian Coordinate System.
All proper graphs include the following: Labelled xaxis, labelled yaxis, appropriate scale+
The Cartesian Plane also includes the following but they are not usually labeled on a graph. Add these labels to your graph now to identify them.
Origin
Quadrant I
Quadrant II
Quadrant III
Quadrant IV
Points are identified by ordered pairs.
What is the proper order?
(x,y)
x is the first coordinate and y
is the second coordinate for any pair
Example 1: Identify the coordinates of the given points.
A(-2,7)
B(-7,-2)
C(2,-7)
D(7,2)
What are the coordinates of the origin?
The coordinates of the origin
Are x=0 and y=0
As a point, O(0,0)
Example 2: Plot the following points.
E(3, 4
F(4, 7)
G(0, 9)
H(8, 0)
I(10, 10)
O(0, 0)
E(3,4)
(x,y)
When a point is on the y-axis, what does it look like?
The x-coordinate of any point on the y-axis is zero. As a point, (0,y)
When a point is on the x-axis, what does it look like?
The y-coordinate any point on the x-axis is zero. As a point, (x,0)
