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1/2^(2n-2)

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



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The solution

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  oo          
 ___          
 \  `         
  \    2 - 2*n
  /   2       
 /__,         
n = 1         
$$\sum_{n=1}^{\infty} \left(\frac{1}{2}\right)^{2 n - 2}$$
Sum((1/2)^(2*n - 2), (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\left(\frac{1}{2}\right)^{2 n - 2}$$
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
$$a_{n} = \left(\frac{1}{2}\right)^{2 n - 2}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty}\left(2^{2 n} 2^{2 - 2 n}\right)$$
Let's take the limit
we find
False

False
The rate of convergence of the power series
The answer [src]
4/3
$$\frac{4}{3}$$
4/3
Numerical answer [src]
1.33333333333333333333333333333
1.33333333333333333333333333333
The graph
Sum of series 1/2^(2n-2)

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