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Solution 21890: Finding the Minimum or Maximum (Vertex) of a Function Using the TI-83 Family, TI-84 Plus Family, and TI-Nspire™ Handheld in TI-84 Plus Mode.

How do I find the minimum or maximum of a function using the TI-83 family, TI-84 Plus family and TI-Nspire handheld in TI-84 Plus Mode?

To find the minimum or maximum of a function using the TI-83 family, TI-84 Plus family and TI-Nspire handheld in TI-84 Plus Mode, follow the example below.

For example:

Find the maximum of the function (-3x^2 - 6x + 2)

1) Press [Y=] to access the Y= editor. For Y1, input (-3x^2-6x+2).

2) Press [GRAPH] to graph the parabola.
3) Press [2nd] [TRACE] [4] to select the "maximum" command from the CALC menu.
4) The handheld will prompt for a "Left Bound." Using the arrow keys, move the cursor to the left side of the function (past the maximum point) and press [ENTER].

5) The handheld will prompt for a "Right Bound." Using the arrow keys, move the cursor to the right side of the function (past the maximum point) and press [ENTER].

6) The handheld will prompt for a "Guess." Using the arrow keys, move the cursor as close as possible to the actual maximum point and press [ENTER].

The handheld will display the maximum point as a coordinate pair (-.99999,5). (-.99999) is approximately equivalent to (-1).

Please see the TI-83 Plus Family and TI-84 Plus Family guidebooks for additional information.

TI-Nspire handheld in TI-84 Plus mode users may refer to the TI-84 Plus family guidebook.