# Lesson 4

Using Technology to Work with Sequences

Let’s use technology to create a sequence.

### Problem 1

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

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

### Problem 2

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

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

### Problem 3

*Technology required*. Open a blank spreadsheet.

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

### Problem 4

*Technology required*. Open a blank spreadsheet.

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

### Problem 5

Here is the graph of a sequence.

- Explain how you know this sequence is arithmetic.
- Explain how you know this sequence is not geometric.

### Problem 6

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

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