How To Draw Slope Fields On Ti 84

If you're taking a calculus class, this might be of interest to you.

Slope fields can be useful for visualizing differential equations. By looking at them, you can imagine where a function might go. This small (less than 1 KB) calculator program I've been working on will take a derivative as a function of x, y, or both, and draw a slope field based on it. The program, called "slpfield," is compatible with the TI-83 Plus, TI-84 Silver Edition, and equivalent TI calculators. You will need to use TI Connect and a connector cable to install the Slope Field Calculator and Generator on your graphing calculator.

Click here to download the Slope Field Generator.

Shown here: A slope field as drawn by the TI-89. With the Slope Field Generator, made with TI-BASIC, the TI-83 and TI-84 models too can generate slope fields.

TI 89 Slope Field

How to use the Slope Field Generator

1) Copy the program to your calculator. If you don't have the cable to do this, chances are good that somebody you know does and would be willing to let you borrow their cable.

2) Launch the program by pressing the PRGM button on your TI-83 or TI-84 series calculator, selecting SLPFIELD, and pressing enter twice.

3) Type in the derivative that you'd like to find a slope field for, in terms of X and Y, for Str1 (which will appear on your calculator's screen.) Make sure you put double quotes around your expression. (Alpha key > +). Press Enter.

Slope Field Generator Input

4) For "non-eval expr.," type in a part of your derivative that cannot equal zero. This is important. For example, if the derivative you're finding a slope field for is X/Y, type in Y for non-eval expr. What the program does is, whenever the non-eval expression is equal to 0, it skips drawing a slope for that point. You can use this to avoid errors, like "Error: Divide by 0."

5) I suggest typing in 10 for "X frequency" and 8 for "Y frequency." These values tell how many slope field lines to draw. Press enter and voila, your calculator should begin drawing the slope field.

Slope Field X over Y

This is an example of a slope field that was calculated by the Slope Field Calculator and Generator.

Tags: Calculator, Mathematics, Programming, TI-83 Plus, TI-89

This entry was posted on May 5, 2009 at 7:00 pm and is filed under Academics, Software. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.