Texas Instruments TITANIUM TI-89 - Manual (Page 309)

Basic Function Graphing 309
From the Home Screen or a Program From the Home Screen or a Program From the Home Screen or a Program From the Home Screen or a Program
You can also define and evaluate a function from the Home screen or a program.
• Use the Define and Graph commands. Refer to:
- “Graphing a Function Defined on the Home Screen” and “Graphing a Piecewise
Defined Function” in Additional Graphing Topics.
- “Overview of Entering a Function” in Programming.
• Store an expression directly to a function variable. Refer to:
- “Storing and Recalling Variable Values” in Operating the Calculator.
- “Creating and Evaluating User-Defined Functions” in Calculator Home Screen.
Note: User-defined functions can have almost any name. However, if you want them to
appear in the Y= Editor, use function names y1(x) , y2(x) , etc.
Selecting Functions to Graph Selecting Functions to Graph Selecting Functions to Graph Selecting Functions to Graph
Regardless of how many functions are defined in the Y= Editor, you can select the ones
you want to graph.
Selecting or Deselecting Functions Selecting or Deselecting Functions Selecting or Deselecting Functions Selecting or Deselecting Functions
Press 8 # to display the Y= Editor.
A “Ÿ” indicates which functions will be graphed the next time you display the Graph
screen.