II. Setting a Window - Finding One That Works

B. Examples

1. Polynomial Examples

For these examples, we will use several of the techniques covered in part A of this module.

i) Example 1: Graph the function . For this function we will use the ZDecimal and ZStandard windows. Enter the function by accessing the button and entering the function. Then enter and then 4 for ZDecimal. To graph using ZStandard, enter and then 6.

ZOOM Menu
Enter the
function.
Use ZOOM 4.
Use ZOOM 6.

You can see that either one of these windows is good enough to use. However, the ZDecimal window is the better one to use since it is a friendly window and the TRACE will move in increments of 0.1.

ii) Example 2: Graph the function using ZOOM 4 and ZOOM 6.

Enter the function.
Using ZOOM 4.
Using ZOOM 6.

Since these windows do not give a good graph, use the TABLE to find the window. Notice in the graphs above that the function crosses the x-axis between -2 and -1 and around 5. Access the TABLE window and enter several values of X between -4 and 8 to determine the appropriate Y values. Once you have a good idea of the values of the function, set the window to fit the graph. You may need to try more than one window to get a good picture, but the TABLE will help you find a good starting point.

TABLE Values
Set a Window
Graph