Solve Series Proof Homework: 0<b<1 Convergence & Limit

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Homework Statement



Let 0<b<1, show that \sum^{n}_{r=1} (1/rb - \frac{n<sup>1-b</sup>}{1-b}) converges as n goes to infinity and denote the limit by \beta = \beta(b).

Also, show that \sum^{infinity}_{n=1} \frac{(-1)<sup>n-1</sup>}{n<sup>b</sup>} + \beta(21-b - 1) = 0

Homework Equations


The Attempt at a Solution



Absolutely clueless!

**Sorry for the bad formatting, for I am new to PF.
 
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Try an integral test...
 
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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