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Suma de la serie ((3*n-2)*(x+1)^(n+1))/((n+1)^3*3^n)



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Solución

Ha introducido [src]
  oo                        
____                        
\   `                       
 \                     n + 1
  \   (3*n - 2)*(x + 1)     
   )  ----------------------
  /               3  n      
 /         (n + 1) *3       
/___,                       
n = 1                       
$$\sum_{n=1}^{\infty} \frac{\left(3 n - 2\right) \left(x + 1\right)^{n + 1}}{3^{n} \left(n + 1\right)^{3}}$$
Sum(((3*n - 2)*(x + 1)^(n + 1))/(((n + 1)^3*3^n)), (n, 1, oo))
Respuesta [src]
    //          /                   /   1   x\\                  \     //          /           /   1   x\            /   1   x\\                  \       //          /                   /   1   x\\                  \       //          /           /   1   x\            /   1   x\\                  \
    ||          |          8*polylog|3, - + -||                  |     ||          |  8*polylog|3, - + -|   8*polylog|2, - + -||                  |       ||          |          8*polylog|3, - + -||                  |       ||          |  8*polylog|3, - + -|   8*polylog|2, - + -||                  |
    ||/1    x \ |    8              \   3   3/|      |1   x|     |     ||/1    x \ |           \   3   3/            \   3   3/|      |1   x|     |       ||/1    x \ |    8              \   3   3/|      |1   x|     |       ||/1    x \ |           \   3   3/            \   3   3/|      |1   x|     |
    |||-- + --|*|- ----- + -------------------|  for |- + -| <= 1|     |||-- + --|*|- ------------------- + -------------------|  for |- + -| <= 1|       |||-- + --|*|- ----- + -------------------|  for |- + -| <= 1|       |||-- + --|*|- ------------------- + -------------------|  for |- + -| <= 1|
    ||\24   24/ |  1   x                2     |      |3   3|     |     ||\24   24/ |               2                     2     |      |3   3|     |       ||\24   24/ |  1   x                2     |      |3   3|     |       ||\24   24/ |               2                     2     |      |3   3|     |
    ||          |  - + -         /1   x\      |                  |     ||          |        /1   x\               /1   x\      |                  |       ||          |  - + -         /1   x\      |                  |       ||          |        /1   x\               /1   x\      |                  |
    ||          |  3   3         |- + -|      |                  |     ||          |        |- + -|               |- + -|      |                  |       ||          |  3   3         |- + -|      |                  |       ||          |        |- + -|               |- + -|      |                  |
    ||          \                \3   3/      /                  |     ||          \        \3   3/               \3   3/      /                  |       ||          \                \3   3/      /                  |       ||          \        \3   3/               \3   3/      /                  |
    ||                                                           |     ||                                                                         |       ||                                                           |       ||                                                                         |
- 2*|<             oo                                            | + 3*|<                   oo                                                    | - 2*x*|<             oo                                            | + 3*x*|<                   oo                                                    |
    ||           ____                                            |     ||                 ____                                                    |       ||           ____                                            |       ||                 ____                                                    |
    ||           \   `                                           |     ||                 \   `                                                   |       ||           \   `                                           |       ||                 \   `                                                   |
    ||            \     -n        n                              |     ||                  \       -n        n                                    |       ||            \     -n        n                              |       ||                  \       -n        n                                    |
    ||             \   3  *(1 + x)                               |     ||                   \   n*3  *(1 + x)                                     |       ||             \   3  *(1 + x)                               |       ||                   \   n*3  *(1 + x)                                     |
    ||              )  ------------                 otherwise    |     ||                    )  --------------                       otherwise    |       ||              )  ------------                 otherwise    |       ||                    )  --------------                       otherwise    |
    ||             /            3                                |     ||                   /             3                                       |       ||             /            3                                |       ||                   /             3                                       |
    ||            /      (1 + n)                                 |     ||                  /       (1 + n)                                        |       ||            /      (1 + n)                                 |       ||                  /       (1 + n)                                        |
    ||           /___,                                           |     ||                 /___,                                                   |       ||           /___,                                           |       ||                 /___,                                                   |
    \\           n = 1                                           /     \\                 n = 1                                                   /       \\           n = 1                                           /       \\                 n = 1                                                   /
$$3 x \left(\begin{cases} \left(\frac{x}{24} + \frac{1}{24}\right) \left(\frac{8 \operatorname{Li}_{2}\left(\frac{x}{3} + \frac{1}{3}\right)}{\left(\frac{x}{3} + \frac{1}{3}\right)^{2}} - \frac{8 \operatorname{Li}_{3}\left(\frac{x}{3} + \frac{1}{3}\right)}{\left(\frac{x}{3} + \frac{1}{3}\right)^{2}}\right) & \text{for}\: \left|{\frac{x}{3} + \frac{1}{3}}\right| \leq 1 \\\sum_{n=1}^{\infty} \frac{3^{- n} n \left(x + 1\right)^{n}}{\left(n + 1\right)^{3}} & \text{otherwise} \end{cases}\right) - 2 x \left(\begin{cases} \left(\frac{x}{24} + \frac{1}{24}\right) \left(- \frac{8}{\frac{x}{3} + \frac{1}{3}} + \frac{8 \operatorname{Li}_{3}\left(\frac{x}{3} + \frac{1}{3}\right)}{\left(\frac{x}{3} + \frac{1}{3}\right)^{2}}\right) & \text{for}\: \left|{\frac{x}{3} + \frac{1}{3}}\right| \leq 1 \\\sum_{n=1}^{\infty} \frac{3^{- n} \left(x + 1\right)^{n}}{\left(n + 1\right)^{3}} & \text{otherwise} \end{cases}\right) + 3 \left(\begin{cases} \left(\frac{x}{24} + \frac{1}{24}\right) \left(\frac{8 \operatorname{Li}_{2}\left(\frac{x}{3} + \frac{1}{3}\right)}{\left(\frac{x}{3} + \frac{1}{3}\right)^{2}} - \frac{8 \operatorname{Li}_{3}\left(\frac{x}{3} + \frac{1}{3}\right)}{\left(\frac{x}{3} + \frac{1}{3}\right)^{2}}\right) & \text{for}\: \left|{\frac{x}{3} + \frac{1}{3}}\right| \leq 1 \\\sum_{n=1}^{\infty} \frac{3^{- n} n \left(x + 1\right)^{n}}{\left(n + 1\right)^{3}} & \text{otherwise} \end{cases}\right) - 2 \left(\begin{cases} \left(\frac{x}{24} + \frac{1}{24}\right) \left(- \frac{8}{\frac{x}{3} + \frac{1}{3}} + \frac{8 \operatorname{Li}_{3}\left(\frac{x}{3} + \frac{1}{3}\right)}{\left(\frac{x}{3} + \frac{1}{3}\right)^{2}}\right) & \text{for}\: \left|{\frac{x}{3} + \frac{1}{3}}\right| \leq 1 \\\sum_{n=1}^{\infty} \frac{3^{- n} \left(x + 1\right)^{n}}{\left(n + 1\right)^{3}} & \text{otherwise} \end{cases}\right)$$
-2*Piecewise(((1/24 + x/24)*(-8/(1/3 + x/3) + 8*polylog(3, 1/3 + x/3)/(1/3 + x/3)^2), |1/3 + x/3| <= 1), (Sum(3^(-n)*(1 + x)^n/(1 + n)^3, (n, 1, oo)), True)) + 3*Piecewise(((1/24 + x/24)*(-8*polylog(3, 1/3 + x/3)/(1/3 + x/3)^2 + 8*polylog(2, 1/3 + x/3)/(1/3 + x/3)^2), |1/3 + x/3| <= 1), (Sum(n*3^(-n)*(1 + x)^n/(1 + n)^3, (n, 1, oo)), True)) - 2*x*Piecewise(((1/24 + x/24)*(-8/(1/3 + x/3) + 8*polylog(3, 1/3 + x/3)/(1/3 + x/3)^2), |1/3 + x/3| <= 1), (Sum(3^(-n)*(1 + x)^n/(1 + n)^3, (n, 1, oo)), True)) + 3*x*Piecewise(((1/24 + x/24)*(-8*polylog(3, 1/3 + x/3)/(1/3 + x/3)^2 + 8*polylog(2, 1/3 + x/3)/(1/3 + x/3)^2), |1/3 + x/3| <= 1), (Sum(n*3^(-n)*(1 + x)^n/(1 + n)^3, (n, 1, oo)), True))

    Ejemplos de hallazgo de la suma de la serie