Radius and interval of convergence

dcrisci
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Homework Statement



infinity
∑ (x^(n+5))/3n! Find the radius of convergence and interval of convergence
n=0

Homework Equations


The Attempt at a Solution



I got 0 for the radius and 0 for the interval of convergence using the ratio test. This is no right. Can someone please help me? Thank you
 
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dcrisci said:

Homework Statement



infinity
∑ (x^(n+5))/3n! Find the radius of convergence and interval of convergence
n=0

Homework Equations





The Attempt at a Solution



I got 0 for the radius and 0 for the interval of convergence using the ratio test. This is no right. Can someone please help me? Thank you


Show your work.
 
Answer

Here it is
 

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There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

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