onlinetutor.com.au

Answer the following questions for each of the sequences below.

a) Is it an arithmetic sequence, a geometric sequence, or neither?
b) If it is an arithmetic sequence, what is the common difference? If it is a geometric sequence, what is the common ratio?
c) If it is an arithmetic or geometric sequence, what are the next three terms in the sequence?

1) 128, 64, 32, 16, 8, ...

2) -8, 4, 16, 28, 40, ...

3) 9, -6, 4, -2 2/3, 1 7/9, ...

4) 280, 140, 35, 5 5/6, 35/48, ...

5) 10, 10.3, 10.6, 10.9, 11.2, ...

6) -64, 32, -16, 8, -4, ...

7) 98, 84, 69, 53, 36, ...


Answers

1
a) This is a geometric sequence
b) The common ratio is 0.5
c) The next three terms in the sequence are 4, 2, 1.

2
a) Arithmetic
b) +12
c) 52, 64, 76.

3
a) Geometric
b) -2/3
c) -1 5/27, 64/81, -128/243.

4
a) Not an arithmetic or geometric sequence.

5
a) Arithmetic
b) +0.3
c) 11.5, 11.8, 12.1.

6
a) Geometric
b) -0.5
c) 2, -1, 0.5.

7
a) Not an arithmetic or geometric sequence.