Lesson 18

Part III (Introduction to Sequence, continued)

Sometimes it is useful to sum a sequence. The sum of the terms in a sequence is called a series. Series play an important role in Calculus; for now we will just look at a neat symbol used for summing sequences.

The summation symbol Σ is the uppercase Greek letter sigma and is used as a short hand notation for showing the sum of a sequence. The ClassPad has one in 2-D CALC!

1. Using the ClassPad's Summation Symbol

A few words of wisdom: Whenever you try something new on a calculator or software that gives a result, first try an example that you know the answer to!

2. Summing an Arithmetic Sequence

Part III


Practice Exercises

  1. Please open the Main application and clear the window.
  2. Using summation notation, find the sum of the numbers in the sequence an=3n-5 for n=1 to 10.
  3. On the next line, find the sum using the formula for finding the sum of an arithmetic sequence. [Hint: Use a1=3x1-5 and an=3x10-5.]
  4. With both your sums showing, get a screen capture. Paste it into your Lesson18 document (under a title of PART III).
  5. Open the eActivity named L18_PartIII_a in the Lesson 18 folder.
  6. Evaluate the summation in the Verify strip named Exercise 1. Be sure to use 4 lines to reach the final answer (see the example inside the eActivity for more details).
  7. With your Verify window open, get a screen capture. Add two blank spaces following the first screen capture and then paste this one.
  8. Save your eActivity as L18_PartIII_a_your initials.
  9. Open the eActivity named L18_PartIII_b in the Lesson 18 folder.
  10. Read through the eActivity and complete the summation inside the strip labeled Summation. This activity is design to show you that some summations converge to a single number. In Calculus, you will learn a great deal more about converging series.
  11. With you Main window open and the summation showing as a decimal, get a screen capture. Add two blank spaces following the second screen capture and then paste this one.
  12. Save your eActivity as L18_PartIII_b_your initials.

Part IV

Reflection Exercises

You have just completed the eighteenth lesson in ClassPad 101. Excellent. You are almost done! Please take a few moments to copy and paste the following three questions at the end of your Lesson 18 document and answer them.

  1. Approximately how long did it take you to complete this lesson?
  2. Which activity did you find particularly useful?
  3. Did you find any part of this activity difficult to follow? If so, which part? Also, how did you overcome the difficulty?

Assessment 18: Introduction to Sequence