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Sum of series/ 4x

Sum of series 4x


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The solution

You have entered [src] 
  oo     
 __      
 \ `     
  )   4*x
 /_,     
n = 2
$$\sum_{n=2}^{\infty} 4 x$$ 
Sum(4*x, (n, 2, oo))
The radius of convergence of the power series
Given number:
$$4 x$$
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
$$a_{n} = 4 x$$
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] 
oo*x
$$\infty x$$ 
oo*x

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