Does xn Converge? A Comparison Test

Mattofix
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Homework Statement



Does xn converge (Sum from n=1 to infinity) of xn = 1/(n + SQRTn)

Homework Equations



Using comparision test

The Attempt at a Solution



I separted into fractions of 1/SQRTn - 1/(1 + SQRTn) and i know that both of these diverge since the power of n is less than one but am stuck as to whether is converges or diverges and how to prove it...
 
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\frac{1}{n+n}\leq \frac{1}{n+\sqrt{n}}
 
therefore xn divereges...?
 
yeah that is right, since the harmonic series diverges, it also diverges when we multiply it by a constant.
 
sutupidmath said:
yeah that is right, since the harmonic series diverges, it also diverges when we multiply it by a constant.
Non-zero constant.

Not to offend you but that is what I like to call a "physics-type mistake".
 
Kummer said:
Non-zero constant.

Not to offend you but that is what I like to call a "physics-type mistake".

yeah that is what i actually meant, but thnx for pointing it out. and not am not offended in any way.
 
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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