What Is the Correct Formula for the Radius of Convergence?

lom · 2009-10-13T17:44:01+00:00

\sum \frac{n^2}{3^nz^n}\\ \frac{1}{R}=\lim_{n->\infty}\sqrt[n]{|\sum \frac{n^2}{3^nz^n}|}\\ what to do now?

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lom

[tex]\sum \frac{n^2}{3^nz^n}\\[/tex]

[tex]\frac{1}{R}=\lim_{n->\infty}\sqrt[n]{|\sum \frac{n^2}{3^nz^n}|}\\[/tex]

what to do now?

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Mark44

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What's the question? Also, I don't believe that your formula for 1/R is correct.