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# Geometric Sequences Exercises

### Example 1

Determine whether the sequence is geometric.

1,

### Example 2

Determine whether the sequence is geometric.

3,6,9,12,...

### Example 3

Determine whether the sequence is geometric.

10, 15, 22.5, 33.75, ...

### Example 4

Determine whether the sequence is geometric.

3, 12, 48, 192, ...

### Example 5

Determine whether the sequence is geometric.

.9, .8, .7, .6, ...

### Example 6

Determine if the sequence is geometric or not.

1,-1,1,-1,...

### Example 7

Determine if the sequence is geometric or not.

-2, 14, -98, 686, ...

### Example 8

Determine if the sequence is geometric or not.

3, -15, -75, 375, ...

### Example 9

Find the first four terms of the geometric sequence with

a1 = 7 and r = 3

### Example 10

Find the first four terms of the geometric sequence with

a1 = 100 and

### Example 11

Find the first four terms of the geometric sequence with

a1 = 2 and r = 0.5

### Example 12

Find the first four terms of the geometric sequence with

a1 = 8 and r = -4

### Example 13

Find the first four terms of the geometric sequence with

a1 = 3 and r = 1

### Example 14

A geometric sequence has a1 = 4 and r = 5. Find

a) a2

b) a3

c) a4

d) an

### Example 15

A geometric sequence has a1 = 3 and . Find

a) a2

b) a3

c) a4

d) an

### Example 16

A general geometric sequence has first term a1 and common ratio r. Find

a) a2

b) a3

c) a4

d) an, the general formula for the nth term.

### Example 17

A geometric sequence has a = 8 and r = 0.2. Find a5.

### Example 18

A geometric sequence has a = 2 and r = -5. Find a7.

### Example 19

A geometric sequence has a = 0.125 and r = 2. Find a20.

### Example 20

Find a and r for the geometric sequence with the given terms.

a7 = 640 and a8 = -1280

### Example 21

Find a and r for the geometric sequence with the given terms.

a4 = 1.2 and a5 = 0.24

### Example 22

Find a and r for the geometric sequence with the given terms.

a4 = -3.125 and a5 = 0.78125

### Example 23

Find a and r for the geometric sequence with the given terms.

a11 = 1 and a13 = 0.0625

### Example 24

Find a and r for the geometric sequence with the given terms.

a4 = 51.2 and a7 = 26.2144