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sqrt(n+1)/(n^2+ln^2n)

Sum of series sqrt(n+1)/(n^2+ln^2n)



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The solution

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  oo              
____              
\   `             
 \       _______  
  \    \/ n + 1   
   )  ------------
  /    2      2   
 /    n  + log (n)
/___,             
n = 1             
$$\sum_{n=1}^{\infty} \frac{\sqrt{n + 1}}{n^{2} + \log{\left(n \right)}^{2}}$$
Sum(sqrt(n + 1)/(n^2 + log(n)^2), (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\frac{\sqrt{n + 1}}{n^{2} + \log{\left(n \right)}^{2}}$$
It is a series of species
$$a_{n} \left(c x - x_{0}\right)^{d n}$$
- power series.
The radius of convergence of a power series can be calculated by the formula:
$$R^{d} = \frac{x_{0} + \lim_{n \to \infty} \left|{\frac{a_{n}}{a_{n + 1}}}\right|}{c}$$
In this case
$$a_{n} = \frac{\sqrt{n + 1}}{n^{2} + \log{\left(n \right)}^{2}}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty}\left(\frac{\sqrt{n + 1} \left(\left(n + 1\right)^{2} + \log{\left(n + 1 \right)}^{2}\right)}{\sqrt{n + 2} \left(n^{2} + \log{\left(n \right)}^{2}\right)}\right)$$
Let's take the limit
we find
True

False
The rate of convergence of the power series
The graph
Sum of series sqrt(n+1)/(n^2+ln^2n)

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