Lesson 4

Using Technology to Work with Sequences

Problem 1

Technology required. Open a blank spreadsheet. In A1, type 2 and enter.

1. What should you type into cell A2 to generate the sequence 2, 4, 8, 16, 32, . . . when you fill down the column?
2. What should you type into cell A2 to generate the sequence 2, 4, 6, 8, 10, . . . when you fill down the column?

Solution

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Problem 2

Technology required. Open a blank spreadsheet. In A1, type 400 and enter.

1. What should you type into cell A2 to generate the sequence 400, 200, 100, 50, 25, . . . when you fill down the column?
2. What should you type into cell A2 to generate the sequence 400, 325, 250, 175, 100, . . . when you fill down the column?

Solution

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Problem 3

Technology required. Open a blank spreadsheet.

1. If cell A1 = 5 and cell A2 = A1 * 3 + 2, what are the first 5 terms of the sequence?
2. If cell A1 = 1 and cell A2 = (A1 + 2) * 3, what are the first 5 terms of the sequence?
3. If cell A1 = 2 and cell A2 = (A1 + 2) * 3, what are the first 5 terms of the sequence?

Solution

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Problem 4

Technology required. Open a blank spreadsheet.

1. Find the first 5 terms of a geometric sequence that starts with -5 and has a growth factor of -1.
2. Find the first 5 terms of a geometric sequence that starts with -20 and has a growth factor of 0.5.
3. Find the first 5 terms of an arithmetic sequence that starts with -20 and has an rate of change of 5.
4. Find the first 5 terms of an arithmetic sequence that starts with 43 and has an rate of change of -7.

Solution

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Problem 5

Here is the graph of a sequence.

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1. Explain how you know this sequence is arithmetic.
2. Explain how you know this sequence is not geometric.

Solution

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(From Unit 1, Lesson 3.)

Problem 6

The first two terms of a geometric sequence are 6 and 3.

1. Explain why there is only one geometric sequence with these first two terms.
2. What are the next 3 terms of this geometric sequence?

Solution

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(From Unit 1, Lesson 2.)