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49/(2n+1)(2n)

Sum of series 49/(2n+1)(2n)



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The solution

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  oo             
 ___             
 \  `            
  \      49      
   )  -------*2*n
  /   2*n + 1    
 /__,            
n = 2            
$$\sum_{n=2}^{\infty} 2 n \frac{49}{2 n + 1}$$
Sum((49/(2*n + 1))*(2*n), (n, 2, oo))
The radius of convergence of the power series
Given number:
$$2 n \frac{49}{2 n + 1}$$
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
$$a_{n} = \frac{98 n}{2 n + 1}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty}\left(\frac{n \left(2 n + 3\right)}{\left(n + 1\right) \left(2 n + 1\right)}\right)$$
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 49/(2n+1)(2n)

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