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arctan1/n^2+n+1

Sum of series arctan1/n^2+n+1



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The solution

You have entered [src]
  oo                   
____                   
\   `                  
 \    /atan(1)        \
  \   |------- + n + 1|
  /   |    2          |
 /    \   n           /
/___,                  
n = 1                  
$$\sum_{n=1}^{\infty} \left(\left(n + \frac{\operatorname{atan}{\left(1 \right)}}{n^{2}}\right) + 1\right)$$
Sum(atan(1)/n^2 + n + 1, (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\left(n + \frac{\operatorname{atan}{\left(1 \right)}}{n^{2}}\right) + 1$$
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
$$a_{n} = n + 1 + \frac{\pi}{4 n^{2}}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty}\left(\frac{n + 1 + \frac{\pi}{4 n^{2}}}{n + 2 + \frac{\pi}{4 \left(n + 1\right)^{2}}}\right)$$
Let's take the limit
we find
True

False
The rate of convergence of the power series
The answer [src]
oo
$$\infty$$
oo
Numerical answer
The series diverges
The graph
Sum of series arctan1/n^2+n+1

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