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32 votes
32 votes
HURRY!

Which of the following is a geometric sequence?
1, 2, 4, 6, 8, 10, ..
-1, 0, 1, 2, 3, ...
2, -2, 2, -2, 2, -2, ...
5, 3, 1, -1, -3, ...

User Rodney Lambert
by
3.3k points

1 Answer

17 votes
17 votes

Answer:

C

Explanation:

In a geometric sequence there is a common ratio. The common ratio is a number that you multiply each number of the sequence to get the next number.

A.

1, 2, 4, 6, 8, 10, ...

2/1 = 2

4/2 = 2

It looks like the common ratio is 2, but try the next division: 6/4 = 3/2

It is not 2, so there is no common ratio, and this is not a geometric sequence.

B.

-1, 0, 1, 2, 3, ...

0/-1 = 0

1/0 = undefined

There is no common ratio.

C.

-2/2 = -1

2/(-2) = -1

-2/2 = -1

The common ratio is -1.

This is a geometric sequence.

D.

3/5 = 3/5

1/3 = 1/3

No common ratio.

Answer: C

User Zmilojko
by
3.0k points