How to Simplify a Series with Basic Algebra?

Thread starter kuahji
Start date Apr 20, 2008
Tags

Algebra Basic algebra

Apr 20, 2008

kuahji

\sum (2^(2n)-(-7)^n)/(11^n)

The book has that expression equal to
\sum (4/11)^n - \sum (-7/11)^n

I'm not seeing how the first part changes to (4/11)^n. Wouldn't it be (2^2+2^n) & not 4^n? Or is there something else I'm missing?

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Apr 20, 2008

nicksauce

Science Advisor

Homework Helper

Fact:
(x^y)^z = x^{yz}.
Does that help you out?

Apr 20, 2008

kuahji

Crude, nm. 2am & math doesn't mix sometimes. ^_^

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