Finding the minimum or Maximum Value of a Quadratic Function Using the TI-86
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| Goal: |
Find the minimum value of  . |
Graph  in the window XMin=–4,XMax=4, YMin=–6,Ymax=10. |
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| Procedure: |
| Press more to get the Math Menus. Select FMin. See screen below |
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| See Left Bound? (Lower left of screen) |
| Move Cursor to the left of the lowest point on graph. |
| Press Enter, See Right Bound? (lower left of screen ) |
| Move cursor to the right side of lowest point on graph. |
| Press Enter. See Guess? (lower left of screen). See screen below. |
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| Move cursor to lowest point and press Enter. Make sure your calculator is set with its float over 9 places. See screen below. |
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| See x = 1and y = –1. Lower part of screen. |
| The Minimum value of f(x) is – 1, the y value. |
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| Goal: |
Find the Maximum value of  . |
Graph  in the window XMin=–4,XMax=4, YMin=–6,Ymax=10. |
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| Procedure: |
| Press more to get the Math Menus. Select FMax See screen below |
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| See Left Bound? (Lower left of screen) |
| Move cursor to the left of the highest point on graph. |
| Press Enter. See Right bound? (lower left of screen) |
| Move cursor to the right of the highest point on graph. See screen below |
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| Press Enter. See Guess? (lower left of screen). |
| Move cursor to the highest point on graph. |
| Press Enter. See picture below. |
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| See x = –1 and y = 1, lower part of screen. |
| The Maximum value of f(x) is 1, the y value. |
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