There are several ways to enter a function into the TI-89 graphing calculator. For basic use, we recommend simply entering a function into the equation editor and then working with it from there.

To begin, press Y= to access the equation editor (the Y= menu). The TI-89 can accommodate up to 99 functions.

Simply type in the algebraic expression used to define the function. For example, to enter the quadratic function f defined by , type

X ^ 2 + 3 X 7 ENTER

Once the function is entered, then you can perform a variety of tasks; for example, evaluate the function at a given input value, graph the function, make a table of functional values.