A closed form for $\int_0^1 \frac{\left(\log (1+x)\right)^3}{x}dx$? I would like some help to find a closed form for the following integral:$$\int_0^1 \frac{\left(\log (1+x)\right)^3}{x}dx $$ I was told it could be calculated in a closed form. I've already proved that $$\int_0^1 \frac{\log (1+x)}{x}dx  = \frac{\pi^2}{12}$$ using power series expansion. 
Thank you.
 A: Hints:
Substitute $x=\frac{t}{1-t}$, followed by $t=1-u$, and then expand the denominator via partial fractions:
$$\begin{align}
\mathcal{I}
&=\int_{0}^{1}\frac{\ln^3{\left(1+x\right)}}{x}\,\mathrm{d}x\\
&=\int_{0}^{\frac12}\frac{(1-t)\ln^3{\left(\frac{1}{1-t}\right)}}{t}\,\frac{1}{(1-t)^2}\mathrm{d}t\\
&=-\int_{0}^{\frac12}\frac{\ln^3{\left(1-t\right)}}{t(1-t)}\,\mathrm{d}t\\
&=-\int_{\frac12}^{1}\frac{\ln^3{\left(u\right)}}{u(1-u)}\,\mathrm{d}u\\
&=-\int_{\frac12}^{1}\frac{\ln^3{\left(u\right)}}{u}\,\mathrm{d}u-\int_{\frac12}^{1}\frac{\ln^3{\left(u\right)}}{1-u}\,\mathrm{d}u\\
&=-\left[\frac{\ln^4{(u)}}{4}\right]_{\frac12}^{1}-\int_{\frac12}^{1}\frac{\ln^3{\left(u\right)}}{1-u}\,\mathrm{d}u\\
&=\frac{\ln^4{(2)}}{4}-\int_{\frac12}^{1}\frac{\ln^3{\left(u\right)}}{1-u}\,\mathrm{d}u.\\
\end{align}$$
The final integral $\int_{\frac12}^{1}\frac{\ln^3{\left(u\right)}}{1-u}\,\mathrm{d}u$ is hardly trivial, but neither is it terribly difficult.
A: First note that 
\begin{align}
\int \frac{\ln^{2}(1+x)}{x} \, dx = - 2 \, Li_{3}(1+x) + 2 \, Li_{2}(1+x) \, \ln(1+x) + \ln(-x)  \, \ln^{2}(1+x)
\end{align}
for which
\begin{align}
I_{2} = \int_{0}^{1} \frac{\ln^{2}(1+x)}{x} \, dx = \frac{\zeta(3)}{4}.
\end{align}
Now,
\begin{align}
\int \frac{\ln^{3}(1+x)}{x} \, dx = \int \ln(1+x) \, \frac{\ln^{2}(1+x)}{x} \, dx 
\end{align}
can be integrated by parts. This leads to
\begin{align}
\int \frac{\ln^{3}(1+x)}{x} \, dx &= \ln(1+x) \left( - 2 \, Li_{3}(1+x) + 2 \, Li_{2}(1+x) \, \ln(1+x) + \ln(-x)  \, \ln^{2}(1+x) \right) \\
& - \int \frac{- 2 \, Li_{3}(1+x) + 2 \, Li_{2}(1+x) \, \ln(1+x) + \ln(-x)  \, \ln^{2}(1+x)}{1+x} \, dx \\
&= \ln(1+x) \left( - 2 \, Li_{3}(1+x) + 2 \, Li_{2}(1+x) \, \ln(1+x) + \ln(-x)  \, \ln^{2}(1+x) \right) \\
& \hspace{10mm} + 6 Li_{4}(1+x) + Li_{2}(1+x) \, \ln^{2}(1+x) - 4 Li_{3}(1+x) \, \ln(1+x)
\end{align}
This leads to 
\begin{align}
I_{3} &= \int_{0}^{1} \frac{\ln^{3}(1+x)}{x} \, dx \\
&= 6 Li_{4}(2) + \ln^{2}(2) \, Li_{2}(2) - 4 \ln(2) \, Li_{3}(2) - 6 \zeta(4) - \frac{7}{4} \, \ln(2) \, \zeta(3) \\
&= \frac{\pi^{4}}{15} + \frac{\pi^{2}}{4} \, \ln^{2}(2) - \frac{21}{4} \, \zeta(3) \, \ln(2) - \frac{1}{4} \, \ln^{4}(2) - 6 Li_{4}\left(\frac{1}{2} \right)
\end{align}
A: By using the generalization
$$\int_0^1\frac{\ln^n(1+x)}{x}dx=\frac{\ln^{n+1}(2)}{n+1}+n!\zeta(n+1)+\sum_{k=0}^n k!{n\choose k}\ln^{n-k}(2)\operatorname{Li}_{k+1}\left(\frac12\right)$$
setting $n=3$ and  subbing the special values of $$\operatorname{Li}_2(1/2)=\frac12\zeta(2)-\frac12\ln^22$$ and $$\operatorname{Li}_3(1/2)=\frac78\zeta(3)-\frac12\ln2\zeta(2)+\frac16\ln^32$$
we get the desired closed form of the integral in the question.
A: Letting $u = \log(1+x)$,
$$ \begin{align} \int_{0}^{1} \frac{\log^{3}(1+x)}{x} \ dx &= \int_{0}^{\log 2} \frac{u^{3}}{e^{u}-1} e^{u} \ du \\ &= \int_{0}^{\log 2} \frac{u^{3}}{1-e^{-u}} \ du \\ &= \int_{0}^{\log 2} u^{3} \sum_{n=0}^{\infty} e^{-nu} \ du \\ &= \sum_{n=0}^{\infty} \int_{0}^{\log 2} u^{3} e^{-nu} \ du \\ &= \int_{0}^{\log 2} u^{3} \ du + \sum_{n=1}^{\infty}\int_{0}^{\log 2} u^{3} e^{-nu} \ du \\ &= \frac{\log^{4}(2)}{4} + \sum_{n=1}^{\infty}\int_{0}^{\log 2} u^{3} e^{-nu} \ du .\end{align}$$
Then integrating by parts 3 times, 
$$\begin{align} \int_{0}^{1} \frac{\log^{3}(1+x)}{x} \ dx &= \frac{\log^{4}(2)}{4} -\sum_{n=1}^{\infty} e^{-nu} \left(\frac{6}{n^{4}} + \frac{6u}{n^{3}} + \frac{3 u^{2}}{n^{2}} + \frac{u^{3}}{n} \right)\Bigg|^{\log 2}_{0} \\ &= \frac{\log^{4}(2)}{4} - \sum_{n=1}^{\infty} \left[\frac{1}{2^{n}} \left(\frac{6}{n^{4}} + \frac{6 \log 2}{n^{3}} + \frac{3 \log^{2} (2)}{n^{2}} + \frac{\log^{3}(2)}{n}\right)  - 6 \zeta(4) \right] \\ &= -\frac{3\log^{4}(2)}{4 } - 6 \text{Li}_{4} \left(\frac{1}{2} \right) - 6 \log (2) \ \text{Li}_{3} \left(\frac{1}{2} \right)-3 \log^{2}(2) \text{Li}_{2} \left(\frac{1}{2} \right) + 6 \zeta(4) \\ &\approx 0.1425141979 . \end{align}$$
The answer could of course be simplified using the known values of $\text{Li}_{2} \left(\frac{1}{2} \right)$, $\text{Li}_{3} \left( \frac{1}{2}\right) $, and $\zeta(4)$. 
A: $\newcommand{\bbx}[1]{\,\bbox[15px,border:1px groove navy]{\displaystyle{#1}}\,}
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\begin{align}
&\bbox[10px,#ffd]{\int_{0}^{1}{\ln^{3}\pars{1 + x} \over x}\,\dd x} =
\int_{1}^{2}{\ln^{3}\pars{x} \over x - 1}\,\dd x =
\int_{1}^{1/2}{\ln^{3}\pars{1/x} \over 1/x - 1}
\pars{-\,{\dd x \over x^{2}}}
\\[5mm] = &\
-\int_{1/2}^{1}{\ln^{3}\pars{x} \over x\pars{1 - x}}\,\dd x =
\overbrace{-\int_{1/2}^{1}{\ln^{3}\pars{x} \over x}\,\dd x}
^{\ds{{1 \over 4}\ln^{4}\pars{2}}}\ -\
\int_{1/2}^{1}{\ln^{3}\pars{x} \over 1 - x}\,\dd x
\\[5mm] = &\
{1 \over 4}\ln^{4}\pars{2} -
\bracks{\left.-\ln\pars{1 - x}\ln^{3}\pars{x}\right\vert_{\ 1/2}^{\ 1} -
3\int_{1/2}^{1}\mrm{Li}'_{2}\pars{x}\ln^{2}\pars{x}\,\dd x}
\\[5mm] = &\
-\,{3 \over 4}\ln^{4}\pars{2} -3\,\mrm{Li}_{2}\pars{1 \over 2}\ln^{2}\pars{2} -
6\int_{1/2}^{1}\mrm{Li}'_{3}\pars{x}\ln\pars{x}\,\dd x
\\[5mm] = &\
-\,{3 \over 4}\ln^{4}\pars{2} -
3\,\mrm{Li}_{2}\pars{1 \over 2}\ln^{2}\pars{2} -
6\,\mrm{Li}_{3}\pars{1 \over 2}\ln\pars{2} + 6\int_{1/2}^{1}\mrm{Li}'_{4}\pars{x}\,\dd x
\\[5mm] = &\
-\,{3 \over 4}\ln^{4}\pars{2} -
3\,\mrm{Li}_{2}\pars{1 \over 2}\ln^{2}\pars{2} -
6\,\mrm{Li}_{3}\pars{1 \over 2}\ln\pars{2}
\\[2mm] & \phantom{\,\,\,}+\
6\,\mrm{Li}_{4}\pars{1} - 6\mrm{Li}_{4}\pars{1 \over 2} 
\end{align}
$\ds{\mrm{Li}_{4}\pars{1} = \zeta\pars{4} = \pi^{4}/90}$ and values of $\ds{\mrm{Li}_{2}\pars{1/2}}$ and
$\ds{\mrm{Li}_{3}\pars{1/2}}$
are already known such that the final result is reduced to:
\begin{align}
&\bbox[10px,#ffd]{\int_{0}^{1}{\ln^{3}\pars{1 + x} \over x}\,\dd x}
\\[5mm] = &\
\bbx{{\pi^{4} \over 15} + {1 \over 4}\,\pi^{2}\ln^{2}\pars{2} -
{1 \over 4}\,\ln^{4}\pars{2} -
6\,\mrm{Li}_{4}\pars{1 \over 2} - {21 \over 4}\,\ln\pars{2}\zeta\pars{3}}
\\[5mm] \approx &\ 0.1425
\end{align}
A: do you know this results ?
$\int_0^1 \frac{\left(\log (1+x)\right)^2}{x}dx=(ζ(3))/4$
