(adsbygoogle = window.adsbygoogle || []).push({}); [SOLVED] radius of convergence

1. The problem statement, all variables and given/known data

Let D be th region in the xy plane in which the series

[tex]\sum_{k=1}^{\infty}\frac{(x+2y)^k}{k}[/tex]

converges. Describe D.

2. Relevant equations

3. The attempt at a solution

By the ratio test, we find the radius of converge of the series in x+ 2y to be 1. So, the series will converge when |x+2y| < 1. This region is a rectangle.

What is wrong with this?

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# Homework Help: Radius of convergence

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