TI-84 Plus CE Graphing Calculator For Dummies, 3rd Edition
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Sometimes functions are composed together. This may look like, f(g(x)). Function composition is really just substituting one function into another function. Fortunately, you can use your TI-84 Plus calculator to accomplish this task.

Using your graph to compose functions

If you want a graphical representation of function composition, follow these steps:

  1. Enter your functions in the Y= editor.

    Functions are entered in Y1 and Y2 as shown in the first screen.

    image0.jpg
  2. To place your cursor in an open equation in the Y= editor, use the following keys:

    image1.jpg
  3. Press [ALPHA][TRACE] to access the Y-VAR menu and choose the first function you need.

  4. Press [(] and press [ALPHA][TRACE] to access the Y-VAR menu and choose the second function you need.

  5. Press [(], then press

    image2.jpg

    and press [)] twice.

    See the second screen.

  6. Press [GRAPH] to see the graph of the composed function.

    See the third screen.

Using your calculator to compose functions

To evaluate composed functions at a specific x-value, follow these steps:

  1. Enter your functions in the Y= editor.

    Functions are entered in Y1 and Y2 as shown in the first screen.

    image3.jpg
  2. Press [2nd][MODE] to access the Home screen.

  3. Press [ALPHA][TRACE] to access the Y-VAR menu and choose the first function you need.

    See the second screen.

  4. Press [(] and press [ALPHA][TRACE] to access the Y-VAR menu and choose the second function you need.

  5. Press [(], then enter an x-value and press [)] twice.

  6. Press [ENTER] to see the result of your function composition.

    See the third screen.

About This Article

This article is from the book:

About the book author:

Jeff McCalla is a mathematics teacher at St. Mary's Episcopal School in Memphis, TN. He cofounded the TI-Nspire SuperUser group, and received the Presidential Award for Excellence in Science & Mathematics Teaching.

C.C. Edwards is an educator who has presented numerous workshops on using TI calculators.

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