Define your own function
Name a formula once with Define, then call it with any value.
The Classic CAS model can remember a formula under a name, like f(x) = x² + 1. After that you can write f(3) and get an answer, or use f inside other calculations and graphs. Add more inputs by listing them: f(x,y).
Classic CAS
Start on the main screen: Press home to open the Home menu (Calculator, Graphs, Settings, and more). Choose Calculator, or press esc to go back to the calculation page.
Open the Actions menu (menu, 1) and choose Define (the first item).
menu11Type the function name and input: f(x). Then type = followed by the formula. Press the right arrow once to step out of the exponent after typing the 2.
f(x)=x^2▶+1Press enter. The screen answers Done.
enterNow use it. Type f(3) and press enter.
f(3)enter
You should seeDefine f(x)=x^2+1 Done 10
Classic CAS · A function of two inputs
Start on the main screen: Press home to open the Home menu (Calculator, Graphs, Settings, and more). Choose Calculator, or press esc to go back to the calculation page.
Choose Define again. List both inputs in the brackets, separated by a comma.
menu11f(x,y)=x×y+1enterCall it with two values: f(3,4).
f(3,4)enter
You should seef(3,4) 13
Tips
- Defining the same name again replaces the old function.
- Variables like x need not hold a value for a Define to work, because they are only placeholders.