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Sum of series 1/4^x



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The solution

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  oo     
 ___     
 \  `    
  \    -x
  /   4  
 /__,    
n = 1    
$$\sum_{n=1}^{\infty} \left(\frac{1}{4}\right)^{x}$$
Sum((1/4)^x, (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\left(\frac{1}{4}\right)^{x}$$
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
$$a_{n} = \left(\frac{1}{4}\right)^{x}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty} 1$$
Let's take the limit
we find
True

False
The answer [src]
    -x
oo*4  
$$\infty 4^{- x}$$
oo*4^(-x)

    Examples of finding the sum of a series