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  • Sum of series:
  • sqrt((n+4)/((n^4)+4)) sqrt((n+4)/((n^4)+4))
  • (7^n-3^n)/21^n (7^n-3^n)/21^n
  • sin(pi/2^(n-1)) sin(pi/2^(n-1))
  • sin(n*x)/n^2
  • Identical expressions

  • (four n)!/(n!)^ four *(x/4)^(n+ one)
  • (4n)! divide by (n!) to the power of 4 multiply by (x divide by 4) to the power of (n plus 1)
  • (four n)! divide by (n!) to the power of four multiply by (x divide by 4) to the power of (n plus one)
  • (4n)!/(n!)4*(x/4)(n+1)
  • 4n!/n!4*x/4n+1
  • (4n)!/(n!)⁴*(x/4)^(n+1)
  • (4n)!/(n!)^4(x/4)^(n+1)
  • (4n)!/(n!)4(x/4)(n+1)
  • 4n!/n!4x/4n+1
  • 4n!/n!^4x/4^n+1
  • (4n)! divide by (n!)^4*(x divide by 4)^(n+1)
  • Similar expressions

  • (4n)!/(n!)^4*(x/4)^(n-1)

Sum of series (4n)!/(n!)^4*(x/4)^(n+1)



=

The solution

You have entered [src]
  oo                 
____                 
\   `                
 \              n + 1
  \   (4*n)! /x\     
   )  ------*|-|     
  /      4   \4/     
 /     n!            
/___,                
n = 0                
$$\sum_{n=0}^{\infty} \left(\frac{x}{4}\right)^{n + 1} \frac{\left(4 n\right)!}{n!^{4}}$$
Sum((factorial(4*n)/factorial(n)^4)*(x/4)^(n + 1), (n, 0, oo))
The radius of convergence of the power series
Given number:
$$\left(\frac{x}{4}\right)^{n + 1} \frac{\left(4 n\right)!}{n!^{4}}$$
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
$$a_{n} = \frac{\left(\frac{x}{4}\right)^{n + 1} \left(4 n\right)!}{n!^{4}}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty}\left(\left|{\frac{\left(\frac{x}{4}\right)^{- n - 2} \left(\frac{x}{4}\right)^{n + 1} \left(4 n\right)!}{n!^{4} \left(4 n + 4\right)!}}\right| \left(n + 1\right)!^{4}\right)$$
Let's take the limit
we find
$$1 = \frac{1}{64 \left|{x}\right|}$$
$$1 = \frac{0.015625}{\left|{x}\right|}$$
False
The answer [src]
  //  _                                         \
  || |_  /1/4, 1/2, 3/4 |     \                 |
  || |   |              | 64*x|  for 64*|x| <= 1|
  ||3  2 \     1, 1     |     /                 |
  ||                                            |
  ||      oo                                    |
  ||    ____                                    |
x*|<    \   `                                   |
  ||     \     -n  n                            |
  ||      \   4  *x *(4*n)!                     |
  ||       )  -------------         otherwise   |
  ||      /          4                          |
  ||     /         n!                           |
  ||    /___,                                   |
  \\    n = 0                                   /
-------------------------------------------------
                        4                        
$$\frac{x \left(\begin{cases} {{}_{3}F_{2}\left(\begin{matrix} \frac{1}{4}, \frac{1}{2}, \frac{3}{4} \\ 1, 1 \end{matrix}\middle| {64 x} \right)} & \text{for}\: 64 \left|{x}\right| \leq 1 \\\sum_{n=0}^{\infty} \frac{4^{- n} x^{n} \left(4 n\right)!}{n!^{4}} & \text{otherwise} \end{cases}\right)}{4}$$
x*Piecewise((hyper((1/4, 1/2, 3/4), (1, 1), 64*x), 64*|x| <= 1), (Sum(4^(-n)*x^n*factorial(4*n)/factorial(n)^4, (n, 0, oo)), True))/4

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