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  • Sum of series:
  • ln(1-1/n^2) ln(1-1/n^2)
  • cos*π*n cos*π*n
  • cosn/n cosn/n
  • 56724.3*10^-1 56724.3*10^-1

  • Identical expressions

  • log(one - three /n^ two)
  • logarithm of (1 minus 3 divide by n squared )
  • logarithm of (one minus three divide by n to the power of two)
  • log(1-3/n2)
  • log1-3/n2
  • log(1-3/n²)
  • log(1-3/n to the power of 2)
  • log1-3/n^2
  • log(1-3 divide by n^2)

  • Similar expressions

  • log(1+3/n^2)
Sum of series/ log(1-3/n^2)

Sum of series log(1-3/n^2)


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The solution

You have entered [src] 
  oo             
____             
\   `            
 \       /    3 \
  \   log|1 - --|
  /      |     2|
 /       \    n /
/___,            
n = 1
$$\sum_{n=1}^{\infty} \log{\left(1 - \frac{3}{n^{2}} \right)}$$ 
Sum(log(1 - 3/n^2), (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\log{\left(1 - \frac{3}{n^{2}} \right)}$$
It is a series of species
$$a_{n} \left(c x - x_{0}\right)^{d n}$$
- power series.
The radius of convergence of a power series can be calculated by the formula:
$$R^{d} = \frac{x_{0} + \lim_{n \to \infty} \left|{\frac{a_{n}}{a_{n + 1}}}\right|}{c}$$
In this case
$$a_{n} = \log{\left(1 - \frac{3}{n^{2}} \right)}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty} \left|{\frac{\log{\left(1 - \frac{3}{n^{2}} \right)}}{\log{\left(1 - \frac{3}{\left(n + 1\right)^{2}} \right)}}}\right|$$
Let's take the limit
we find
True

False
Numerical answer [src] 
-1.98728714190023218939231840466 + 3.14159265358979323846264338328*i
-1.98728714190023218939231840466 + 3.14159265358979323846264338328*i

    Examples of finding the sum of a series

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