SOLUTION: Question: Find the sums of the following geometric series. 1 + 3 + 9 +...+2187. What I've tried so far... So: know:a=1 r=3 tn=2187 find:??? For this

Question 247854: Question: Find the sums of the following geometric series. 1 + 3 + 9 +...+2187.
What I've tried so far...
So: know:a=1
r=3
tn=2187
find:???
For this problem, wouldn't I have to find how many terms are in the sequence first? Then whatever n is, I plug that into another equation?
I'm so lost...please help!
Answer by mathitutor(25) (Show Source): You can put this solution on YOUR website!
This is a standard geometric progression,
3^0 + 3^1 + 3^2 + ... + 3^7
There is a standard formula for summation of terms of a geometric progression series. Use that to solve this.
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