Texas Instruments TITANIUM TI-89 - Manual (Page 476)

Additional Graphing Topics 476
two-piece functions. For three or more pieces, it may be easier to create a multi-
statement, user-defined function.
Using the When Function Using the When Function Using the When Function Using the When Function
To define a two-piece function, use the syntax:
when(condition, trueExpression, falseExpression)
For example, suppose you want to graph a function with two pieces.
For three or more pieces, you can use nested when functions.
When: Use expression:
x < 0 M x
x | 0 5 cos(x)
In the Y= Editor:
The function is “pretty
printed” in this form.
Enter the function in this
form.