Graphing Equations with a Graphing Utility
Most graphing calculators require similar techniques to graph an equation. The equations sometimes have to be manipulated so they are written in the style y=_____. The TI-84 Plus, and many other calculator makes and models, have a mode function, which allows the window (the screen for viewing the graph) to be altered so the pertinent parts of a graph can be seen. For example, the equation [latex]y=2x - 20[/latex] has been entered in the TI-84 Plus shown in Figure 9a. In Figure 9b, the resulting graph is shown. Notice that we cannot see on the screen where the graph crosses the axes. The standard window screen on the TI-84 Plus shows [latex]-10\le x\le 10[/latex], and [latex]-10\le y\le 10[/latex]. See Figure 9c.
![This is an image of three side-by-side calculator screen captures. The first screen is the plot screen with the function y sub 1 equals two times x minus twenty. The second screen shows the plotted line on the coordinate plane. The third screen shows the window edit screen with the following settings: Xmin = -10; Xmax = 10; Xscl = 1; Ymin = -10; Ymax = 10; Yscl = 1; Xres = 1.](https://s3-us-west-2.amazonaws.com/courses-images-archive-read-only/wp-content/uploads/sites/1225/2015/12/CNX_CAT_Figure_02_01_009abcN.jpg)
![This is an image of two side-by-side calculator screen captures. The first screen is the window edit screen with the following settings: Xmin = negative 5; Xmax = 15; Xscl = 1; Ymin = -30; Ymax = 10; Yscl = 1; Xres =1. The second screen shows the plot of the previous graph, but is more centered on the line.](https://s3-us-west-2.amazonaws.com/courses-images-archive-read-only/wp-content/uploads/sites/1225/2015/12/CNX_CAT_Figure_02_01_010ab.jpg)
Example 3: Using a Graphing Utility to Graph an Equation
Use a graphing utility to graph the equation: [latex]y=-\frac{2}{3}x-\frac{4}{3}\\[/latex].Solution
Enter the equation in the y= function of the calculator. Set the window settings so that both the x- and y- intercepts are showing in the window.![This image is of a line graph on an x, y coordinate plane. The x-axis has numbers that range from negative 3 to 4. The y-axis has numbers that range from negative 3 to 3. The function y = -2x/3 + 4/3 is plotted.](https://s3-us-west-2.amazonaws.com/courses-images-archive-read-only/wp-content/uploads/sites/1225/2015/12/CNX_CAT_Figure_02_01_011.jpg)
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- College Algebra. Provided by: OpenStax Authored by: OpenStax College Algebra. Located at: https://cnx.org/contents/[email protected]:1/Preface. License: CC BY: Attribution.