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



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Solución

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

    Ejemplos de hallazgo de la suma de la serie