Mister Exam

Sum of series 2i+1



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The solution

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  oo           
 __            
 \ `           
  )   (2*i + 1)
 /_,           
i = 1          
i=1(2i+1)\sum_{i=1}^{\infty} \left(2 i + 1\right)
Sum(2*i + 1, (i, 1, oo))
The radius of convergence of the power series
Given number:
2i+12 i + 1
It is a series of species
ai(cxx0)dia_{i} \left(c x - x_{0}\right)^{d i}
- power series.
The radius of convergence of a power series can be calculated by the formula:
Rd=x0+limiaiai+1cR^{d} = \frac{x_{0} + \lim_{i \to \infty} \left|{\frac{a_{i}}{a_{i + 1}}}\right|}{c}
In this case
ai=2i+1a_{i} = 2 i + 1
and
x0=0x_{0} = 0
,
d=0d = 0
,
c=1c = 1
then
1=limi(2i+12i+3)1 = \lim_{i \to \infty}\left(\frac{2 i + 1}{2 i + 3}\right)
Let's take the limit
we find
True

False
The rate of convergence of the power series
1.07.01.52.02.53.03.54.04.55.05.56.06.50100
The answer [src]
oo
\infty
oo
Numerical answer
The series diverges
The graph
Sum of series 2i+1

    Examples of finding the sum of a series