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Suma de la serie 1/((2n-1)(2n+1))x^(2n+1)



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Solución

Ha introducido [src]
  oo                     
____                     
\   `                    
 \           2*n + 1     
  \         x            
  /   -------------------
 /    (2*n - 1)*(2*n + 1)
/___,                    
n = 2                    
$$\sum_{n=2}^{\infty} \frac{x^{2 n + 1}}{\left(2 n - 1\right) \left(2 n + 1\right)}$$
Sum(x^(2*n + 1)/(((2*n - 1)*(2*n + 1))), (n, 2, oo))
Respuesta [src]
  //   /15      2                         \               \
  ||   |-- - 5*x    /          2\         |               |
  || 4 |2           \-15 + 15*x /*atanh(x)|               |
  ||x *|--------- + ----------------------|               |
  ||   |     4                  5         |               |
  ||   \    x                2*x          /      | 2|     |
  ||---------------------------------------  for |x | <= 1|
  ||                   15                                 |
  ||                                                      |
x*|<              oo                                      |
  ||            ____                                      |
  ||            \   `                                     |
  ||             \        2*n                             |
  ||              \      x                                |
  ||               )  ---------                otherwise  |
  ||              /           2                           |
  ||             /    -1 + 4*n                            |
  ||            /___,                                     |
  \\            n = 2                                     /
$$x \left(\begin{cases} \frac{x^{4} \left(\frac{\frac{15}{2} - 5 x^{2}}{x^{4}} + \frac{\left(15 x^{2} - 15\right) \operatorname{atanh}{\left(x \right)}}{2 x^{5}}\right)}{15} & \text{for}\: \left|{x^{2}}\right| \leq 1 \\\sum_{n=2}^{\infty} \frac{x^{2 n}}{4 n^{2} - 1} & \text{otherwise} \end{cases}\right)$$
x*Piecewise((x^4*((15/2 - 5*x^2)/x^4 + (-15 + 15*x^2)*atanh(x)/(2*x^5))/15, |x^2| <= 1), (Sum(x^(2*n)/(-1 + 4*n^2), (n, 2, oo)), True))

    Ejemplos de hallazgo de la suma de la serie