Tracing Features of the TI-84 Plus C Calculator - dummies

Tracing Features of the TI-84 Plus C Calculator

By Jeff McCalla, C. C. Edwards

The TI-84 Plus C calculator allows you to change the TraceStep. The TraceStep is the amount the x-value changes each time you press right- or left-arrow keys when tracing a function. The default TraceStep is approximately 0.1515151515. Customizing the TraceStep is easy and can be done by following these steps:

  1. Press [WINDOW] to access the Window editor.

    See the second screen.

  2. Use the down-arrow to move your cursor the last line, titled TraceStep.

  3. Enter your desired TraceStep.

After pressing [TRACE], your Trace cursor will move by the amount of the TraceStep value you entered each time you use

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Be careful, changing the TraceStep will automatically change the Xmax value as well. This can be quite a shock the first time it happens.

There’s a hidden feature that works after you hit [TRACE]. See the first screen in the following figure. If you want to start tracing your function at a specific value of the independent variable x, just key in that value and press [ENTER] when you’re finished. (The value you assign to x must be between Xmin and Xmax; if it isn’t, you get an error message.)

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When you’re entering the x-value, your calculator displays the number you’re entering in the border at the bottom of your screen, as shown in the second screen.

After you press [ENTER], the Trace cursor moves to the point on the graph having the x-coordinate you just entered. See the third screen. This is an easy way to quickly substitute x-values into a function and see the output (y-values) as well as the nice visual of the Trace cursor on the graph itself. Pretty neat stuff, don’t you think?