The zeroes of a function are the x-values where the graph of the function intersects the x-axis. Another name for the zero of a function is the x-intercept of a function.

In order to find the zeroes of a function, a graph must already be displayed on the screen. To learn how to enter and graph a function, go to Graphing a Function. Note that the function, = , below crosses the x-axis in 3 places; thus, there are 3 zeroes.

Screen Picture of TI-83 Calculator

To find one of the zeroes, press 2nd TRACE [CALC], then select 2:Zero.

Screen Picture of TI-83 Calculator Screen Picture of TI-83 Calculator

To locate the leftmost zero, use the Left Arrow Key to move the flashing cursor slightly to the left of the zero, then press ENTER.

Screen Picture of TI-83 Calculator Screen Picture of TI-83 Calculator

A right arrow above the graph marks the left bound selection.

Now use the Right Arrow Key to move the flashing cursor slightly to the right of the zero, and then press ENTER.

Screen Picture of TI-83 Calculator Screen Picture of TI-83 Calculator

Note that both the left bound and right bound are marked with small arrows above the graph.

Now move the cursor as close to the zero as possible and then press ENTER again. The last screen shows that this zero is approximately x = -2.33.

Screen Picture of TI-83 Calculator Screen Picture of TI-83 Calculator

The other two zeros may be calculated by repeating the above process for each of them. Below are the results.
The results are approximately x = 0.20 and x = 2.13.

Screen Picture of TI-83 Calculator Screen Picture of TI-83 Calculator

 



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