IV. Special Graphs

B. Greatest Integer Function

The greatest integer function (also called a step function) is actually a piecewise defined function with a special definition. The function has the notation f(x)=||x|| or f(x)=[[x]] when it is written, but the TI-86 designates this function by using f(x)=int(x) and is found in the MATH NUM menu. This function is the greatest integer less than or equal to x. So, f(1)=1 and f(1.4)=1. Since this is a piecewise function you should use DOT mode.

Example: Graph the function f(x)=||x|| (the greatest integer function). Make sure that you use DOT mode.

Access int using

Enter the function.
and put in DOT.
Graph with ZDECM.
Without DOT
(not good).


A. Derivative
B. Greatest
C. Integral
D. Inverse
E. Piecewise