How to Graph Inequalities on the TI-84 Plus
As with functions on your TI-84 Plus calculator, if the inequality sign in the definition of the inequality is highlighted, then that inequality will be graphed; if it isn’t highlighted, it won’t be graphed. The first screen shows that the first two inequalities will be graphed, but the third won’t. To change the highlighted status of an inequality sign, place the cursor on that sign and press [ENTER].
You graph the inequalities defined in the Y= and X= editors the same way you graph a normal function. You either define the variables in the Window editor and press [GRAPH] or use one of the Zoom commands. When the graph is displayed, you see three options at the bottom of the graph screen, as in the third screen.
The Inequality Graphing app adds the ShadeRes variable to the Window editor, as illustrated in the second screen. This variable can be set to any integer 3 through 8. A setting of 3 places the lines in the shaded graph close together and 8 places them far apart. The default value is 6 as shown in the second screen, and this setting works just fine for most graphs, as illustrated in the third screen.