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sqrt((n+4)/((n^4)+4))

Sum of series sqrt((n+4)/((n^4)+4))



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The solution

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  oo               
____               
\   `              
 \         ________
  \       / n + 4  
   )     /  ------ 
  /     /    4     
 /    \/    n  + 4 
/___,              
n = 1              
n=1n+4n4+4\sum_{n=1}^{\infty} \sqrt{\frac{n + 4}{n^{4} + 4}}
Sum(sqrt((n + 4)/(n^4 + 4)), (n, 1, oo))
The radius of convergence of the power series
Given number:
n+4n4+4\sqrt{\frac{n + 4}{n^{4} + 4}}
It is a series of species
an(cxx0)dna_{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:
Rd=x0+limnanan+1cR^{d} = \frac{x_{0} + \lim_{n \to \infty} \left|{\frac{a_{n}}{a_{n + 1}}}\right|}{c}
In this case
an=n+4n4+4a_{n} = \sqrt{\frac{n + 4}{n^{4} + 4}}
and
x0=0x_{0} = 0
,
d=0d = 0
,
c=1c = 1
then
1=limn(n+4(n+1)4+4n+5n4+4)1 = \lim_{n \to \infty}\left(\frac{\sqrt{n + 4} \sqrt{\left(n + 1\right)^{4} + 4}}{\sqrt{n + 5} \sqrt{n^{4} + 4}}\right)
Let's take the limit
we find
True

False
The rate of convergence of the power series
1.07.01.52.02.53.03.54.04.55.05.56.06.503
The answer [src]
  oo              
_____             
\    `            
 \        _______ 
  \     \/ 4 + n  
   \   -----------
   /      ________
  /      /      4 
 /     \/  4 + n  
/____,            
n = 1             
n=1n+4n4+4\sum_{n=1}^{\infty} \frac{\sqrt{n + 4}}{\sqrt{n^{4} + 4}}
Sum(sqrt(4 + n)/sqrt(4 + n^4), (n, 1, oo))
The graph
Sum of series sqrt((n+4)/((n^4)+4))

    Examples of finding the sum of a series