Sr Examen

Otras calculadoras

Suma de la serie (1+(-1)^n*x^(3n+5))/(3n+1)



=

Solución

Ha introducido [src]
  oo                    
____                    
\   `                   
 \            n  3*n + 5
  \   1 + (-1) *x       
  /   ------------------
 /         3*n + 1      
/___,                   
n = 1                   
$$\sum_{n=1}^{\infty} \frac{\left(-1\right)^{n} x^{3 n + 5} + 1}{3 n + 1}$$
Sum((1 + (-1)^n*x^(3*n + 5))/(3*n + 1), (n, 1, oo))
Respuesta [src]
        //    /                             -pi*I     /       pi*I\      pi*I    /       5*pi*I\\                          \
        ||    |                             ------    |       ----|      ----    |       ------||                          |
        ||    |          /       pi*I\        3       |        3  |       3      |         3   ||                          |
        ||    |     4*log\1 - x*e    /   4*e      *log\1 - x*e    /   4*e    *log\1 - x*e      /|                          |
        ||    |     ------------------ - -------------------------- - --------------------------|                          |
        ||  3 |4           3*x                      3*x                          3*x            |                          |
        ||-x *|-- - ----------------------------------------------------------------------------|                          |
        ||    | 3                                         3                                     |                          |
        ||    \x                                         x                                      /                          |
      5 ||----------------------------------------------------------------------------------------  for And(x <= 1, x > -1)|
oo + x *|<                                           4                                                                     |
        ||                                                                                                                 |
        ||                                      oo                                                                         |
        ||                                    ____                                                                         |
        ||                                    \   `                                                                        |
        ||                                     \        n  3*n                                                             |
        ||                                      \   (-1) *x                                                                |
        ||                                      /   ----------                                             otherwise       |
        ||                                     /     1 + 3*n                                                               |
        ||                                    /___,                                                                        |
        \\                                    n = 1                                                                        /
$$x^{5} \left(\begin{cases} - \frac{x^{3} \left(- \frac{- \frac{4 e^{- \frac{i \pi}{3}} \log{\left(- x e^{\frac{i \pi}{3}} + 1 \right)}}{3 x} + \frac{4 \log{\left(- x e^{i \pi} + 1 \right)}}{3 x} - \frac{4 e^{\frac{i \pi}{3}} \log{\left(- x e^{\frac{5 i \pi}{3}} + 1 \right)}}{3 x}}{x^{3}} + \frac{4}{x^{3}}\right)}{4} & \text{for}\: x \leq 1 \wedge x > -1 \\\sum_{n=1}^{\infty} \frac{\left(-1\right)^{n} x^{3 n}}{3 n + 1} & \text{otherwise} \end{cases}\right) + \infty$$
oo + x^5*Piecewise((-x^3*(4/x^3 - (4*log(1 - x*exp_polar(pi*i))/(3*x) - 4*exp(-pi*i/3)*log(1 - x*exp_polar(pi*i/3))/(3*x) - 4*exp(pi*i/3)*log(1 - x*exp_polar(5*pi*i/3))/(3*x))/x^3)/4, (x <= 1)∧(x > -1)), (Sum((-1)^n*x^(3*n)/(1 + 3*n), (n, 1, oo)), True))

    Ejemplos de hallazgo de la suma de la serie