Radius of convergence question

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SUMMARY

The discussion centers on determining the interval of convergence for the series ∑{n=0 -> ∞} c_n • x^n, which converges at x = -4 and diverges at x = 6. The radius of convergence is established to be at least 4 and not more than 6, leading to the conclusion that the interval of convergence is [-5, 5) as proposed by one participant. The alternative suggestion of [-5, 6) is dismissed due to insufficient information regarding convergence at x = 5.

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Homework Statement


Suppose that the following series converges when x = -4 and diverges when x = 6.
∑{n=0 -> ∞} c_n • x^n

What is the interval of convergence?

The Attempt at a Solution


I think it is [-5,5) but my friend reckons that it is [-5,6). I don't think [-5,6) is correct because this interval would tell us that 5 is a point of convergence but we don't know that... Am I right?
 
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You don't have enough information. All you know for sure is you have a radius of convergence at least 4 and not more than 6.
 

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