Find the sum of the following infinite geometric series, if it exists. 3 + 9 + 27 + 54 +…

Question

Find the sum of the following infinite geometric series, if it exists.  3 + 9 + 27 + 54 +…

terenzreignz · Answer

Look at it, it just keeps getting bigger and bigger... :D
Does it LOOK like it will have a sum?

anonymous · Answer

not with the anwsers it gives me

anonymous · Answer

Does not exist
		
35,897
		
40,178
		
44,845

terenzreignz · Answer

Okay... new approach... what's the common ratio of this series?
(hint: the common ratio is what you get if you divide the second term by the first, and the third term by the second, etc)

anonymous · Answer

3

terenzreignz · Answer

Yes, very good :)
Infinite geometric series WILL NOT HAVE A SUM if the common ratio is not less than 1. (in absolute value of course)

terenzreignz · Answer

In this case, 3 > 1
so the sum does not exist :)

anonymous · Answer

oh ok thanks :)

terenzreignz · Answer

No problem ;)