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5 votes
Given the following geometric sequence, find the 12th term: {2, -4, 8, ...}.

A. -4096

B. 4096

c. 2048

d -2048

User Rithiur
by
8.3k points

2 Answers

3 votes

Answer: -4096

Explanation:

I just did the lesson

User Astqx
by
7.6k points
1 vote
All geometric sequences can be expressed as:

a(n)=ar^(n-1), a=initial term, r=common ratio, n=term number, in this case:

-4/2=8/-4=-2=r and a=2 so:

a(n)=2(-2^(n-1)) so a(12) is going to be:

a(12)=2(-2^(11))=2(-2048)= -4096
User Kingdaro
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8.1k points