Mean Numbers

Here is a problem for you and your students. The numbers are mean until you get to the end when they all become very nice and well-behaved.  

You could give this to your students individually or as a group exploration. Give each person or group a different function and/or different intervals. Choose a function that has several (3 – 5) turning points in the interval. The function should be differentiable on the open interval and continuous on the closed interval.

It is intended that the work be done on a graphing calculator; you will need to carry 6 or 7 decimal places in their work.

Here is a typical problem. A link to the solution is given at the end.

Consider the function f\left( x \right)=\sin \left( x \right) on the closed interval [1, 12].

  1. Write an equation of a line, y\left( x \right),  between the endpoints of the function. Give the decimal value of its slope and give a graph of the function and the line.
  2. Write the equation of a function h\left( x \right) that gives the vertical distance between f\left( x \right) and y\left( x \right). Since f may be both above and below y this function may have positive and negative values.
  3. Graph h and find its critical values. What are these places with respect to the graph of h?
  4. Calculate the derivative of f at the critical values of h.
  5. Interpret your result graphically.

Click here for the solution.


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