# Casio fx-9750GII Notes: Bump Function and Referencing Functions

The "bump" function is well known, useful for approximating the unit impulse:

Bump function displayed on fx-9750GII

To do this piecewise function on my Casio calculator, you must use conditionals, which evaluate to 1 or 0:

I was wondering also how to reference a previously defined function in the Graph equation list. You must use the special bold Y symbol available by pressing F1 while inputting the equation. Here is an example, although the menu is not showing in this picture:

Function reference while in graph equation list

Using this feature, here is the bump function shifted up 1 unit:

Bump function shifted up 1 unit