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lnn/(n^2+3n)

Sum of series lnn/(n^2+3n)



=

The solution

The radius of convergence of the power series
Given number:
$$\frac{\log{\left(n \right)}}{n^{2} + 3 n}$$
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
$$a_{n} = \frac{\log{\left(n \right)}}{n^{2} + 3 n}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty}\left(\frac{\left(3 n + \left(n + 1\right)^{2} + 3\right) \left|{\log{\left(n \right)}}\right|}{\left(n^{2} + 3 n\right) \log{\left(n + 1 \right)}}\right)$$
Let's take the limit
we find
True

False
The rate of convergence of the power series
Numerical answer [src]
0.628832407266384023700636893057
0.628832407266384023700636893057
The graph
Sum of series lnn/(n^2+3n)

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