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(-1)^n

Sum of series (-1)^n



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The solution

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  oo       
 ___       
 \  `      
  \       n
  /   (-1) 
 /__,      
n = 1      
$$\sum_{n=1}^{\infty} \left(-1\right)^{n}$$
Sum((-1)^n, (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\left(-1\right)^{n}$$
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
$$a_{n} = 1$$
and
$$x_{0} = 1$$
,
$$d = 1$$
,
$$c = 0$$
then
$$R = \tilde{\infty} \left(1 + \lim_{n \to \infty} 1\right)$$
Let's take the limit
we find
False
The rate of convergence of the power series
Numerical answer
The series diverges
The graph
Sum of series (-1)^n

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