One of the first topics covered in calculus is the concept of inverse functions. Standard functions map the change of a variable given a specific input. An inverse function takes a value after a change has been made and provides a numeric value that relates the input that generated it. Students must become familiar with generating these functions from standard functions because the functions are used to take their derivatives and integrals at a later point.

Navigate to the "Home" screen on the TI89.

Press the "F2" key, located in the uppermost row of keys to open the algebra dropdown menu.

Select the "Solve" option from the list provided. The menu disappears and the string "Solve(" will appear in the view screen.

Enter the equation to be inverted after the parenthesis.

Type a single comma after the equation.

Type "x" after the comma and close the command with an end parenthesis.

Press the "enter" key located on the lowerright corner of the keypad. An equation is presented on the view screen.

Exchange all "x" and "y" variables. For example, x = 3y + 2 yields y = 3x + 2. This final form is the inverse of the original function.