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((n^2+5n-3)/(4n+7))^n

Sum of series ((n^2+5n-3)/(4n+7))^n



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  oo                 
____                 
\   `                
 \                  n
  \   / 2          \ 
   )  |n  + 5*n - 3| 
  /   |------------| 
 /    \  4*n + 7   / 
/___,                
n = 1                
$$\sum_{n=1}^{\infty} \left(\frac{\left(n^{2} + 5 n\right) - 3}{4 n + 7}\right)^{n}$$
Sum(((n^2 + 5*n - 3)/(4*n + 7))^n, (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\left(\frac{\left(n^{2} + 5 n\right) - 3}{4 n + 7}\right)^{n}$$
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
$$a_{n} = \left(\frac{n^{2} + 5 n - 3}{4 n + 7}\right)^{n}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty}\left(\left(\frac{5 n + \left(n + 1\right)^{2} + 2}{4 n + 11}\right)^{- n - 1} \left|{\left(\frac{n^{2} + 5 n - 3}{4 n + 7}\right)^{n}}\right|\right)$$
Let's take the limit
we find
False

False
The rate of convergence of the power series
The graph
Sum of series ((n^2+5n-3)/(4n+7))^n

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