Timeline for I need Help to evaluate :$\sum_{n=0}^{\infty} \left({\frac{(2n+1)!!}{(2n+2)!!}}\right)^2\frac{1}{(2n+4)^2}$
Current License: CC BY-SA 4.0
6 events
when toggle format | what | by | license | comment | |
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Jun 20 at 15:06 | vote | accept | Mostafa | ||
Jun 20 at 15:06 | vote | accept | Mostafa | ||
Jun 20 at 15:06 | |||||
Jun 20 at 14:51 | comment | added | Dave77 | $Li_2 (t) = \sum_{n=1}^\infty \frac{t^n}{n^2}$. You can obtain an integral expression: $- \ln (1-t) = \sum_{n=1}^\infty \frac{t^n}{n}$. So that $- \int^t_0 \dfrac{\ln (1-t)}{t} dt = \sum_{n=1}^\infty \frac{t^n}{n^2}$ Then $- \int^t_0 \dfrac{\ln (1-t)}{t} dt = Li_2 (t)$. | |
Jun 20 at 14:01 | answer | added | Claude Leibovici | timeline score: 1 | |
Jun 20 at 12:55 | comment | added | openspace | Why do you think the given sum would have an explicit form? The general way of solving such series: let $S(t) = \sum_{n \ge 0} \frac{t^{n+2}}{4(n+2)}$, hence $S'(t) = \sum_{n \ge 0} \frac{t^{n+1}}{4(n+2)} \Rightarrow (S'(t)t)' = \sum_{n \ge 0} t^{n+1}$. Therefore, you'll obtain an ODE to solve. | |
Jun 20 at 12:27 | history | asked | Mostafa | CC BY-SA 4.0 |