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sin^2(n+1)/((n+1)*sqrt(n+1))

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



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The solution

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

    Examples of finding the sum of a series