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Estimation and Limits -- One-Sided Limits

You should use one of the computer algebra systems below with this module. Click on the appropriate icon for your preferred CAS and then arrange your screen so that you can easily move back-and-forth between this window and your CAS window. Click on the appropriate help button for help.

Maple worksheet Mathematica notebook TI-92 Browser Window

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There are many situations in which a small change can make a huge difference.

Let f(x) denote the price of x units of the product described above.

Missing equation


Use your CAS window to graph the function f(x) and to investigate it. Describe any interesting behavior this function has.

Notice that something very peculiar happens when the quantity crosses the value 1,000. The price for 999 items is $1,998 but the price for 1,000 items is only $1,500. By buying one additional item the cost drops $448.00.

This kind of behavior, although mathematically strange, is not uncommon. The function f(x) behaves differently on the two sides of the value x = 1,000.

In this kind of situation we use the notation

Missing equation

to describe what happens to the function f(x) when x is close to a but to the right of a, and the notation

Missing equation

to describe what happens to the function f(x) when x is close to a but to the left of a.

In our example above

Missing equation

These limits are called one-sided limits because each one looks at just one side of the value x = a.


Check Your Understanding

For each of the following functions find the two one-sided limits at the indicated point a.

  1. Missing equation

    answer

  2. Missing equation

    answer

  3. Missing equation

    answer

  4. Missing equation

    answer

  5. Missing equation

    answer

  6. Missing equation

    answer

  7. Missing equation

    answer

  8. Missing equation

    answer

  9. Missing equation

    answer


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Copyright c 1995 by Frank Wattenberg, Department of Mathematics, Carroll College, Helena, MT 59625