The graphing calculator program that comes with every Power Macintosh computer is a very powerful tool for doing algebra. This activity will help you to learn how to use this program to graph equations and inequalities.
When you start the graphing calculator, you should see a window similar to this:
You type expressions and equations in the top part of the window. Graphs appear in the bottom part of the window. The buttons on the lower left allow you to zoom in and out. You can see different parts of the graph by dragging the axes with your mouse.
Type the equation y = x and click the Graph button (or hit the return key). Your graph should look something like this:
Use the zoom buttons to zoom in and out. Click on the axes and drag them to see other parts of the graph. Click along the graph to turn on tracing. Drag the box which appears. If you drag slowly and listen carefully, you may hear it "click" when it crosses the x-axis.
Graph the following linear equations (make copies of your graphs on a sheet of graph paper):
 |
 |
 |
To enter a fraction, type something like 2 / 3, then use the right arrow key to leave the denominator. Graph the following linear equations (make copies of your graphs on a sheet of graph paper):
 |
 |
 |
Choose Show Small Keypad from the Equation menu. Type y = | x |. To do the absolute value, first type the x, then select it, then click the absolute value button on the keypad. You can use the right arrow key to get outside the absolute value. Graph the following absolute value equations (make copies of your graphs on a sheet of graph paper):
 |
 |
Type the equation y = nx + 1. A slide control will appear at the bottom of your window:
Click the n and set the lowest value to -5, the highest value to 5, and the number of steps to 20. Click OK.
Use your mouse to click and drag the slider back and forth. What effect does this have on your graph? What role does the n play in this equation?
Click the play button (the little arrow to the right of the n on the controller). What happens?
Click the button again. What happens?
You can also graph inequalities using the graphing calculator program. Type the inequality 3x + 7y < 20. Your graph should look something like this:
Graph each of the following inequalities (make copies of your graphs on a piece of graph paper):
|
|
|
|
|