IV. Special Graphs

E. Piecewise

The TI-89 will graph a piecewise defined function. To do this, you will use the syntax when(condition,trueExpression, falseExpression).The when( option is available via the catalog.

Example: Graph the function: .

Press and select the y1 function.
Go to the catalog and select the when( option.
Type the function. The < is accessed by pressing .
Put the function in dot mode by pressing which is the Style menu. Select 2:Dot and ENTER.
Select and then select 4:ZoomDec.
Press ENTER and the graph is displayed.

To graph a three piece function, use nested when functions.

Example: Graph

The function is entered as

Enter the function.
Graph with ZoomStd.