SOLUTION: What is the summation notation for the series 1 + 0.1 + 0.01 + 0.001?

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Question 293551: What is the summation notation for the series 1 + 0.1 + 0.01 + 0.001?
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
1 + 0.1 + 0.01 + 0.001

a%5B2%5D%2Fa%5B1%5D=%280.1%29%2F%281%29=0.1
a%5B3%5D%2Fa%5B2%5D=%280.01%29%2F%280.1%29=0.1
a%5B4%5D%2Fa%5B3%5D=%280.001%29%2F%280.01%29=0.1

So this is a 4-term geometric series with r=0.1.

a%5Bn%5D=a%5B1%5Dr%5E%28n-1%29
a%5Bn%5D=%281%29%280.1%29%5E%28n-1%29
a%5Bn%5D=%280.1%29%5E%28n-1%29


sum%28a%5Bn%5D%2Cn=1%2C4%29=sum%28+0.1%5E%28n-1%29+%2Cn=1%2C4%29

Edwin