Mister Exam

Sum of series -1/(2*n-1)!



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The solution

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

False
The rate of convergence of the power series
The answer [src]
-sinh(1)
$$- \sinh{\left(1 \right)}$$
-sinh(1)
Numerical answer [src]
-1.17520119364380145688238185060
-1.17520119364380145688238185060
The graph
Sum of series -1/(2*n-1)!

    Examples of finding the sum of a series