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Sum of series (x^(n-1))/(n(n+1))



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The solution

You have entered [src]
  oo           
____           
\   `          
 \       n - 1 
  \     x      
  /   ---------
 /    n*(n + 1)
/___,          
n = 1          
$$\sum_{n=1}^{\infty} \frac{x^{n - 1}}{n \left(n + 1\right)}$$
Sum(x^(n - 1)/((n*(n + 1))), (n, 1, oo))
The answer [src]
/1   (2 - 2*x)*log(1 - x)              
|- + --------------------  for |x| <= 1
|x              2                      
|            2*x                       
|                                      
|      oo                              
|    ____                              
<    \   `                             
|     \         n                      
|      \       x                       
|       )  ----------       otherwise  
|      /            2                  
|     /    n*x + x*n                   
|    /___,                             
\    n = 1                             
$$\begin{cases} \frac{1}{x} + \frac{\left(2 - 2 x\right) \log{\left(1 - x \right)}}{2 x^{2}} & \text{for}\: \left|{x}\right| \leq 1 \\\sum_{n=1}^{\infty} \frac{x^{n}}{n^{2} x + n x} & \text{otherwise} \end{cases}$$
Piecewise((1/x + (2 - 2*x)*log(1 - x)/(2*x^2), |x| <= 1), (Sum(x^n/(n*x + x*n^2), (n, 1, oo)), True))

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