Using the CALC Menu with TI83 Graphs

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Using the CALC Menu with TI-83 Graphs
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• Several interesting features of a graph or graphs
  can be examined using the calculations menu
  through the graphs of a TI-83.

We will look at 1 through 5. 6 and 7 are used in
Calculus.
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1Value

• The value command allows you to easily evaluate a
  function f(x) for a given x value.
• Example 1 Let f(x) x3 2x 4. Find f(-3),
  f(2), and f(3).

• Graph the function.

2. Hit 2nd, TRACE, and 1 to pick VALUE.
3. You can now enter an X value to evaluate.
4. Repeat for each desired f(X) value.
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2zero

• The zero command can be used to find zeros
  (x-intercepts) of a function.
• Example Find the zeros of f(x) x3 2x 4.
• 1. Graph it.

2. Hit 2nd, TRACE, and 2 to pick zero.
3. It asks for a left bound. You have to use the
left arrow to move the cursor to the left until
its x value is less than the zero. Then hit enter.
4. It asks for a right bound. You have to use the
right arrow to move the cursor to the right until
its x value is greater than the zero. Then hit
enter.
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• 5. It will then ask for a guess. Use the arrows
  to move near the zero and hit enter.
• 6. Read your answer!

This can be repeated for functions with multiple
zeros. Each time you choose bounds around the
desired zero.
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• 3 Minimum
• The minimum command finds the smallest value of
  f(x) on an interval.
• It works similar to zero, but you choose your
  bounds around a desired minimum.
• Example Find any local minima of f(x) x3-2x4
• 1. Graph it.

2. Choose the left and right bounds around the
minimum.
3. Guess near the minimum.
4. Read the answer.
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The command 4Maximum works similar to 3Minimum
except you choose bounds around the maximum
values.
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• 5Intersect
• The command intersect can be used to find a point
  where two graphs intersect.
• Example Find all intersections of f(x) x3 -2x
  4 and g(x) x 4.
• 1. Graph them both together.

2. Hit 2nd, TRACE, and 5.
3. You will be asked to pick the first curve.
Move the cursor to see which curve it is on, and
hit enter.
4. You are asked for the second curve. Move the
cursor until it is on the other curve, and hit
enter.
5. Now you are asked for a guess. Where you guess
will determine which intersection is found. Guess
near the one you want.
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• 6. You can repeat for the other intersections.
  Guess near different ones each time.