THE COORDINATE PLANE

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CHAPTER 5
THE COORDINATE PLANE
THE BEGINNING!!
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5.1 THE COORDINATE PLANE
Points are located in reference to two
perpendicular number lines called axes.
The axes intersect at their zero points, a point
called the origin.
The horizontal number line, called the x-axis,
and the vertical number line, called the y-axis,
divide the plane into four quadrants numbered
counter-clockwise.
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The plane containing the x and y axes is called
the coordinate plane or the Cartesian plane.
Points in the coordinate plane are named by
ordered pairs of the form (x, y). The first
number, or x-coordinate, corresponds to the
numbers on the x axis. The second number, or
y-coordinate, corresponds to the numbers on the
y-axis. The ordered pair for the origin is
(0,0).
To graph an ordered pair means to draw a dot at
the point on the coordinate plane that
corresponds to the ordered pair.
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5.2 Relations
A relation is a set of ordered pairs. Relations
can be represented by 1) ordered pairs, 2)
tables, 3) graphs and 4) mapping.
The domain of a relation is the set of all first
coordinates from the ordered pairs in the
relation. The range of the relation is the set
of all second coordinates from the ordered pairs.
For example
A relation
A (2,3), (-2,4), (-1,0), (-4,-5)
3, 4, 0, -5
2, -2, -1, -4
The range
The domain
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The inverse of any relation is obtained by
switching the coordinates in each ordered pair.
For Example
A (2,3), (-2,4), (-1,0), (-4,-5)
A relation
The inverse relation
B (3,2), (4,-2), (0,-1), (-5,-4)