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

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


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The solution

You have entered [src] 
  oo           
 ___           
 \  `          
  \       1    
   )  ---------
  /   n*(n + 2)
 /__,          
n = 1
∑n=1∞1n(n+2)\sum_{n=1}^{\infty} \frac{1}{n \left(n + 2\right)} 
Sum(1/(n*(n + 2)), (n, 1, oo))
The radius of convergence of the power series
Given number:
1n(n+2)\frac{1}{n \left(n + 2\right)}
It is a series of species
an(cx−x0)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+lim⁡n→∞∣anan+1∣cR^{d} = \frac{x_{0} + \lim_{n \to \infty} \left|{\frac{a_{n}}{a_{n + 1}}}\right|}{c}
In this case
an=1n(n+2)a_{n} = \frac{1}{n \left(n + 2\right)}
and
x0=0x_{0} = 0
,
d=0d = 0
,
c=1c = 1
then
1=lim⁡n→∞((n+1)(n+3)n(n+2))1 = \lim_{n \to \infty}\left(\frac{\left(n + 1\right) \left(n + 3\right)}{n \left(n + 2\right)}\right)
Let's take the limit
we find
True

False
The rate of convergence of the power series
1.07.01.52.02.53.03.54.04.55.05.56.06.50.01.0
The answer [src] 
3/4
34\frac{3}{4} 
3/4
Numerical answer [src] 
0.750000000000000000000000000000
0.750000000000000000000000000000
The graph
Sum of series 1/(n(n+2))

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