Calculate MacLaurin Series for Finding the Sum of a Series | Homework Help

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SUMMARY

The discussion focuses on calculating the sum of the series 3 + (9/2!) + (27/3!) + (81/4!) using the MacLaurin series expansion of e^x. The user successfully restructured the series to express it as 3 * Σ (3^n)/(n+1)!, leading to the conclusion that the series can be simplified further. Participants emphasized the importance of correctly handling the first term and suggested re-indexing the summation for clarity and accuracy in computation.

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Homework Statement



"Find the sum of the seires:

3 + (9/2!) + 27/3! +81/4!+ ... "

Homework Equations


e^x = Ʃ n=0 to inf (x^n)/n!

The Attempt at a Solution


=3(1 +3/2! + 9/3! + 27/4! + ...
=3*Ʃ n=0 to inf( (3^n)/(n+1)!)
=Ʃ n=0 to inf( (3^(n+1))/(n+1)!)

. unsure what to do from here, maybe break apart the sigma by re-indexing? I am not sure how to do this. Any help would be greatly appreciated.
 
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Why did you pull out the 3? If you are missing the first term, I would add it manually in the sum (and subtract it outside). This is easier than an index shift.
 

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