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|3^n|

Sum of series |3^n|



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The solution

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  oo      
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  \   | n|
  /   |3 |
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n = 1     
n=13n\sum_{n=1}^{\infty} \left|{3^{n}}\right|
Sum(|3^n|, (n, 1, oo))
The radius of convergence of the power series
Given number:
3n\left|{3^{n}}\right|
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=3re(n)a_{n} = 3^{\operatorname{re}{\left(n\right)}}
and
x0=0x_{0} = 0
,
d=0d = 0
,
c=1c = 1
then
1=limn(3n3n1)1 = \lim_{n \to \infty}\left(3^{n} 3^{- n - 1}\right)
Let's take the limit
we find
False

False

False
The rate of convergence of the power series
1.07.01.52.02.53.03.54.04.55.05.56.06.505000
The answer [src]
oo
\infty
oo
Numerical answer
The series diverges
The graph
Sum of series |3^n|

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