How to Enter Inequalities in the Y= Editor
The Inequality Graphing app on your TI-84 Plus calculator can graph functions and inequalities that are defined in the Y= editor. Follow these steps to define a function or inequality of the form
Press [Y=] to access the Y= editor.
To erase any unwanted functions or inequalities from the Y= editor, use the arrow keys to place the cursor after the equality or inequality symbol in the definition of the unwanted function or inequality and press [CLEAR].
Use the arrow keys to place the cursor on the sign of the function or inequality you are defining.
Press [ALPHA] and press the key under the appropriate equality or inequality symbol.
To get the first screen, press [ALPHA][ZOOM] to enter a less-than or equal sign. Press [ZOOM] because that is the soft key under the less-than or equal symbol appearing in the on-screen prompt at the bottom of the screen.
The equality and inequality symbols appear at the bottom of the screen only when the cursor is on the equality or inequality symbol appearing to the right of one of the functions Y1 through Y9 or Y0.
Press the right-arrow key and enter the definition of the function or inequality.
The definition of the function or inequality is entered the same way you enter the definition of a function. The second screen shows that the inequality
is defined in Y1.
After defining a function or inequality, you can change the inequality sign in this definition by following Steps 2 and 3.