Section 5.2 A Graphing Technology

Relations


A Preview of Lesson 5.2

 

A relation is a set of ordered pairs. This can be done using a graphing calculator.

 

Example 1: Plot the following points on a coordinate plane:

M (4, 7), A (-10, 25), T (-17, -17), and H (23, -11)

 

To do this first you must teach your students how to enter an ordered pair into the calculator. Click here for help.

 

Start with a viewing winow of [-47, 47] by [-31, 31] using a scale of 10 for each axis. This can be done quickly by entering 6 8 . (This sets the scale to integer values.)

 

Clear the coordinate plane by turning off all stat plots and clearing the Y= list.

 

To plot the first point, enter . The cursor appears at the origin and X=0 and Y=0 appears at teh bottom of the screen.

 

Now use the arrow keys to move the cursor to the coordinates of the point you wish to graph. The coordinates of each position of the cursor appear at the bootom of the viewing screen.

 

Press to put a dot at the point.

 

Continue to move the cursor and press to graph the other three points.

 

When finished, you can clear the screen by pressing 1.

 

 

 

 

 

PLEASE NOTE: If you do not need a range as large as the one you get by pressing 8, you can set the WINDOW values in the usual manner or press 6. Using example one, you will find that you cannot plot points at exact integer values by using the cursor, so we must learn another way. (Example 2)

 

 

 

Example 2: Plot G (-4, 5), R (1, 6), A (-3, -6), P (5, -8), and H (0, 7) in the standard viewing window.

Set the standard viewing window (Enter: 6)

Return to the home screen by pressing

You can graph all of the points by linking commands into a series using a colon. (Enter: and chose 1 - Pt-On( appears)

Continue after Pt-On( with - 4 , 5 ) [So it should read Pt-On(-4,5)]

This enters the first point...now do it with the rest of the values above.

 

You can also use line on the DRAW menu to connect the points. (This will help you to analyze the points in relation. You must first clear the screen by pressing 1 before creating a new graph)

 

 

 

 

 

Example 3: Determine if the graphs of (3, 5), (-3, -5), and (0, 7) are on the same line. (What shape do they form if not a line?)

 

For Practice: Do Exercises at the end of section 5-2A

 

 

 


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