Piecewise-Defined Functions


A frequently asked question is, how do I enter and graph a piecewise defined function? For example, suppose the function f is defined as follows:

To enter f, first press to access the MAIN MENU icons. Then press to access the GRPH-TBL screen. The Graph Func screen is displayed. Enter the function as follows:

Y1=X2, [-10,0]
Y2=X, [0,1]
Y3=2, [1,10]

Instead of the beginning and ending numbers of -10 and 10, you may use any number to the left (right) of the specified Xmin (Xmax) in the viewing window.

In general, enter each branch of the function on a different Y= line followed by a comma. After the comma, enter the interval on which the branch is defined. Here are the Casio keystrokes for entering the above function.

Y1=

Y2=

Y3=

Press to obtain the graph. If needed, adjust the window. The graph at right uses the settings Xmin:-3, max:3, scale:1 and Ymin:-2, max:5. scale:1. For convenience, press CTRL to toggle on and off the graph menu at the bottom of the screen.