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sqrt(n+2)-2*sqrt(n-1)+sqrt(n)

Sum of series sqrt(n+2)-2*sqrt(n-1)+sqrt(n)



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The solution

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  oo                                   
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  \   /  _______       _______     ___\
  /   \\/ n + 2  - 2*\/ n - 1  + \/ n /
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n = 1                                  
$$\sum_{n=1}^{\infty} \left(\sqrt{n} + \left(- 2 \sqrt{n - 1} + \sqrt{n + 2}\right)\right)$$
Sum(sqrt(n + 2) - 2*sqrt(n - 1) + sqrt(n), (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\sqrt{n} + \left(- 2 \sqrt{n - 1} + \sqrt{n + 2}\right)$$
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
$$a_{n} = \sqrt{n} - 2 \sqrt{n - 1} + \sqrt{n + 2}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty} \left|{\frac{\sqrt{n} - 2 \sqrt{n - 1} + \sqrt{n + 2}}{- 2 \sqrt{n} + \sqrt{n + 1} + \sqrt{n + 3}}}\right|$$
Let's take the limit
we find
True

False
The rate of convergence of the power series
Numerical answer
The series diverges
The graph
Sum of series sqrt(n+2)-2*sqrt(n-1)+sqrt(n)

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