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

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