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Sum of series x²



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The solution

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  oo    
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 \  `   
  \    2
  /   x 
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x = 1   
x=1x2\sum_{x=1}^{\infty} x^{2}
Sum(x^2, (x, 1, oo))
The radius of convergence of the power series
Given number:
x2x^{2}
It is a series of species
ax(cxx0)dxa_{x} \left(c x - x_{0}\right)^{d x}
- power series.
The radius of convergence of a power series can be calculated by the formula:
Rd=x0+limxaxax+1cR^{d} = \frac{x_{0} + \lim_{x \to \infty} \left|{\frac{a_{x}}{a_{x + 1}}}\right|}{c}
In this case
ax=x2a_{x} = x^{2}
and
x0=0x_{0} = 0
,
d=0d = 0
,
c=1c = 1
then
1=limx(x2(x+1)2)1 = \lim_{x \to \infty}\left(\frac{x^{2}}{\left(x + 1\right)^{2}}\right)
Let's take the limit
we find
True

False
The rate of convergence of the power series
1.07.01.52.02.53.03.54.04.55.05.56.06.50200
The answer [src]
oo
\infty
oo
Numerical answer
The series diverges
The graph
Sum of series x²

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