How to Find Horizontal Asymptotes of a Function on a TI-83

Many functions have no vertical or horizontal asymptotes.
••• Jupiterimages/Comstock/Getty Images

Horizontal asymptotes are the numbers that "y" approaches as "x" approaches infinity. For instance, as "x" approaches infinity and "y" approaches 0 for the function "y=1/x" -- "y=0" is the horizontal asymptote. You can save time in finding horizontal asymptotes by using your TI-83 to create a table of "x" and "y" values of the function, and observing trends in "y" as "x" approaches infinity.

    Access the "Y=?" part of your calculator, and input the function into "Y1."

    Make a table to determine the behavior of the function as "x" approaches infinity. Click on the "Tbl" button. You may set "TblStart" to 20, and the table intervals to 20.

    Display the table, and scroll through the values as "x" gets bigger and bigger. Determine any trends in "y" that occur. For instance, "y" may slowly and infinitesimally trend towards the number 1. If this is the case, then the horizontal asymptote is "y=1."