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Prove that $$\int_0^1x\log\left(1+x^2\right)\left[\log\left(\frac{1-x}{1+x}\right)\right]^3\operatorname{d}\!x$$ $$I=\frac{105}{8}\zeta(3)-\frac{7\pi^2}{4}\ln2-6\pi{G}+3\pi^2-\frac{3}{8}\pi^3-\frac{7}{64}\pi^4$$ where $G$ is the Catalan's constant. Additional reponse at FDP You are almost at the end. $\mathbf{I}\mathbf{\,continue}$ Using integration by parts, we have: $C=3\displaystyle\int_0^1\dfrac{\log^2x\log(1+x^2)}{x}dx-3\displaystyle\int_0^1\dfrac{\log^2x\log(1+x^2)}{1+x}dx-\displaystyle\int_0^1\dfrac{log^3x}{1+x}dx-\displaystyle\int_0^1\dfrac{log^3x}{1+x^2}dx+\displaystyle\int_0^1\dfrac{x\log^3x}{1+x^2}dx$

$D=\displaystyle\dfrac{3}{2}\int_0^1\dfrac{\log^2x\log(1+x^2)}{x}dx-\displaystyle\dfrac{3}{2}\int_0^1\dfrac{\log^2x\log(1+x^2)}{1+x}dx-\displaystyle\dfrac{3}{2}\int_0^1\dfrac{\log^2x\log(1+x^2)}{(1+x)^2}dx-\displaystyle\dfrac{1}{2}\int_0^1\dfrac{log^3x}{(1+x)^2}dx+\displaystyle\dfrac{1}{2}\int_0^1\dfrac{log^3x}{1+x^2}dx$ $2D-C=\displaystyle\int_0^1\dfrac{(1-x)\log^3x\log(1+x^2)}{(1+x)^3}dx=-3\displaystyle\int_0^1\dfrac{log^2x\log(1+x^2)}{(1+x)^2}dx+\displaystyle\int_0^1\dfrac{log^3x}{1+x}dx-\displaystyle\int_0^1\dfrac{xlog^3x}{1+x^2}dx$. } But,$\displaystyle\int_0^1\dfrac{log^3x}{1+x}dx=-\dfrac{7\pi^4}{120}$; and$ \displaystyle\int_0^1\dfrac{xlog^3x}{1+x^2}dx.=-\dfrac{7\pi^4}{1920}$

Remains to be assessed: $ \displaystyle\int_0^1\dfrac{log^2x\log(1+x^2)}{(1+x)^2}dx$, to be continued . Also, $\displaystyle\int_0^1\dfrac{\log^2x\log(1+x^2)}{(1+x)^2}dx=2\displaystyle\int_0^1\dfrac{\log\,x\log(1+x^2)}{x}dx-2\displaystyle\int_0^1\dfrac{\log\,x\log(1+x^2)}{(1+x)}dx-\displaystyle\int_0^1\dfrac{log^2x}{1+x}dx+\displaystyle\int_0^1\dfrac{log^2x}{1+x^2}dx+\displaystyle\int_0^1\dfrac{x\log^2x}{1+x^2}dx$

These integrals are know

$\displaystyle\int_0^1\dfrac{\log\,x\log(1+x^2)}{x}dx=-\dfrac{3}{16}\zeta(3)$; $\displaystyle\int_0^1\dfrac{\log\,x\log(1+x^2)}{(1+x)}dx=-\dfrac{\pi(G)}{2}-\dfrac{\pi^2}{16}ln2+\dfrac{3}{2}\zeta(3)$

Also, $\displaystyle\int_0^1\dfrac{\log^2x\log(1+x^2)}{(1+x)^2}dx=2\displaystyle\int_0^1\dfrac{\log\,x\log(1+x^2)}{x}dx-2\displaystyle\int_0^1\dfrac{\log\,x\log(1+x^2)}{(1+x)}dx-\displaystyle\int_0^1\dfrac{log^2x}{1+x}dx+\displaystyle\int_0^1\dfrac{log^2x}{1+x^2}dx+\displaystyle\int_0^1\dfrac{x\log^2x}{1+x^2}dx$

These integrals are know

$\displaystyle\int_0^1\dfrac{\log\,x\log(1+x^2)}{x}dx=-\dfrac{3}{16}\zeta(3)$; $\displaystyle\int_0^1\dfrac{\log\,x\log(1+x^2)}{(1+x)}dx=-\dfrac{\pi}{2}{G}-\dfrac{\pi^2}{16}ln2+\dfrac{3}{2}\zeta(3);\displaystyle\int_0^1\dfrac{log^2x}{1+x}dx=\dfrac{3}{2}\zeta(3); \displaystyle\int_0^1\dfrac{log^2x}{1+x^2}dx=\dfrac{\pi^3}{16}$

Finally,$\displaystyle\int_0^1\dfrac{log^2x\log(1+x^2)}{(1+x)^2}dx=\dfrac{75}{16}\zeta(3)+{\pi}G+\dfrac{\pi^2}{8}ln2+\dfrac{\pi^3}{16}$

And 2D-C=$\dfrac{297}{16}\zeta(3)-3{\pi}G-\dfrac{3}{8}{\pi^2}ln2-\dfrac{3}{16}{\pi^3}-\dfrac{7}{128}{\pi^4}$ We obtain also the result.

The Artist
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user178256
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  • My approach would be to rewrite log((1-x)/(1+x)) as log(1-x)-log(1+x) and then expand the cube. This will at least break the integral up into smaller chunks. –  Dec 01 '14 at 15:51

2 Answers2

21

Complete solution.

Let $$\displaystyle I=\int_0^1 x\log(1+x^2)\Big[\log\Big(\dfrac{1-x}{1-x}\Big)\Big]^3dx$$

First perform the change of variable $y=\dfrac{1-x}{1+x}$.

$$\displaystyle I=\int_0^1 \dfrac{2(1-x)}{(1+x)^3}\log\Big(\dfrac{2(1+x^2)}{(1+x)^2}\Big)\log^3xdx$$

Notice: $\dfrac{1-x}{(1+x)^3}=\dfrac{2}{(1+x)^3}-\dfrac{1}{(1+x)^2}$

Therefore:

$$I=4\log 2\times B-2\log 2\times A+4D-2C-8F+4E$$

Where:

$A=\displaystyle \int_0^1\dfrac{\log^3x}{(1+x)^2}dx$

$B=\displaystyle \int_0^1\dfrac{\log^3x}{(1+x)^3}dx$

$C=\displaystyle \int_0^1 \dfrac{\log(1+x^2)\log^3x}{(1+x)^2}dx$

$D=\displaystyle \int_0^1 \dfrac{\log(1+x^2)\log^3x}{(1+x)^3}dx$

$E=\displaystyle \int_0^1 \dfrac{\log(1+x)\log^3x}{(1+x)^2}dx$

$F=\displaystyle \int_0^1 \dfrac{\log(1+x)\log^3x}{(1+x)^3}dx$

One can continue like this, using integration by parts:

$\color{red}{C=\displaystyle\int_0^1 \dfrac{3\log^2x\log(1+x^2)}{x}dx-\int_0^1 \dfrac{3\log^2x\log(1+x^2)}{1+x}dx+\int_0^1 \dfrac{x\log^3 x}{1+x}dx-\int_0^1 \dfrac{x^2\log^3 x}{1+x^2}dx+\int_0^1 \dfrac{x\log^3 x}{1+x^2}dx}$(false, see below)

Let's compute $A$:

$\displaystyle A=\int_0^1 \Big[\sum_{n=0}^{+\infty}(n+1)(-1)^nx^n\Big]\log^3 x dx$

$\displaystyle A=-6\sum_{n=0}^{+\infty} \dfrac{(-1)^n}{(n+1)^3}$

$A=-6\times (1-2^{1-3})\zeta(3)=-\dfrac{9}{2}\zeta(3)$

Let's compute $B$:

$\displaystyle B=\dfrac{1}{2}\int_0^1 \Big[(-1)^n(n+2)(n+1)x^n\Big]\log^3 x dx$

$\displaystyle B=-3\sum_{n=0}^{+\infty} \dfrac {(-1)^n}{(n+1)^2}-3\sum_{n=0}^{+\infty} \dfrac {(-1)^n}{(n+1)^3}$

$B=-3\times(1-2^{1-2})\zeta(2)-3\times(1-2^{1-3})\zeta(3)=-\dfrac{3}{2}\zeta(2)-\dfrac{9}{4}\zeta(3)$

$B=-\dfrac{\pi^2}{4}-\dfrac{9}{4}\zeta(3)$

Let's continue.

(it's a bad idea to try to compute $E$ by the way. happily, we're lucky, we don't have to do this)

$\displaystyle E=3\int_0^1 \dfrac{\log^2(x)\log(1+x)}{x}dx-3\int_0^1 \dfrac{\log^2(x)\log(1+x)}{1+x}dx+A$

Let $E_1:=\displaystyle \int_0^1 \dfrac{\log^2(x)\log(1+x)}{x}dx$

Let $\displaystyle E_2:=\int_0^1 \dfrac{\log^2(x)\log(1+x)}{1+x}dx$

(believe me, you don't want to compute $E_2$)

Using integration by parts and partial fraction decomposition: $\displaystyle -8F=12E_2-12E_1+24\int_0^1 \dfrac{\log x\log(1+x)}{x}dx-24\int_0^1 \dfrac{\log x\log(1+x)}{1+x}dx+12\times\int_0^1\dfrac{\log^2x}{(1+x)^2}dx-4B$

Let $\displaystyle F_1=\int_0^1 \dfrac{\log x\log(1+x)}{x}dx$

$\displaystyle F_1=\int_0^1 \Big[\sum_{n=0}^{+\infty}(-1)^n\dfrac{x^{n+1}}{n+1}\Big]\dfrac{\log x}{x}dx$

$F_1=\displaystyle -\sum_{n=0}^{+\infty}\dfrac{(-1)^n}{(n+1)^3}=-(1-2^{1-3})\zeta(3)=-\dfrac{3}{4}\zeta(3)$

Let $\displaystyle F_2=\int_0^1 \dfrac{\log x\log(1+x)}{1+x}dx=-\dfrac{1}{8}\zeta(3)$

(based upon the computation of $K$ in: Other challenging logarithmic integral $\int_0^1 \frac{\log^2(x)\log(1-x)\log(1+x)}{x}dx$ )

Another way to compute $F_2$ knowing that:

$Li_2\Big(\dfrac{1}{2}\Big)=\dfrac{1}{12}\Big(\pi^2-6(\log 2)^2\Big)$

$Li_3\Big(\dfrac{1}{2}\Big)=\dfrac{1}{24}\Big(4(\log 2)^3-2\pi^2\log 2+21\zeta(3)\Big)$

Performing the change of variable $y=\log(1+x)$:

$\displaystyle F_2=\int_0^{\log 2} x\log(e^x-1)dx=\int_0^{\log 2} x^2dx+\int_0^{\log 2} x\log(1-e^{-x})dx$

$\displaystyle F_2=\dfrac{(\log 2)^3}{3}-\sum_{n=1}^{+\infty}\Big(\int_0^{\log 2}\dfrac{xe^{-nx}}{n}dx\Big)$

$\displaystyle F_2=\dfrac{(\log 2)^3}{3}-\sum_{n=1}^{+\infty}\dfrac{1}{n^3}+\log 2\sum_{n=1}^{+\infty}\dfrac{2^{-n}}{n^2}+\sum_{n=1}^{+\infty}\dfrac{2^{-n}}{n^3}$

$\displaystyle F_2=\dfrac{(\log 2)^3}{3}-\zeta(3)+\log 2 Li_2\Big(\dfrac{1}{2}\Big)+Li_3\Big(\dfrac{1}{2}\Big)=-\dfrac{1}{8}\zeta(3)$

Let $\displaystyle F_3=\int_0^1\dfrac{\log^2x}{(1+x)^2}dx$

$\displaystyle F_3=\int_0^1 \Big[\sum_{n=0}^{+\infty}(n+1)(-1)^nx^n\Big]\log^2 x dx$

$\displaystyle F_3=2\sum_{n=0}^{+\infty} \dfrac{(-1)^n}{(n+1)^2}$

$F_3=2\times (1-2^{1-2})\zeta(2)=\zeta(2)=\dfrac{\pi^2}{6}$

Therefore:

$-8F+4E=24F_1-24F_2+12F_3-4B+4A=-24\zeta(3)+3\pi^2$

Addendum:

\begin{align*} C&\overset{\text{IBP}}=3\underbrace{\int_0^1\frac{\ln(1+x^2)\ln^2x}{x}dx}_{\text{IBP}}-3\underbrace{\int_0^1\frac{\ln(1+x^2)\ln^2x}{1+x}dx}_{=K}-\int_0^1\frac{\ln^3x}{1+x}dx+\\&\underbrace{\int_0^1\frac{x\ln^3x}{1+x^2}dx}_{u=x^2}+\underbrace{\int_0^1\frac{\ln^3x}{1+x^2}dx}_{=R}\\ &=\frac{315}{64}\zeta(4)-2\underbrace{\int_0^1\frac{x\ln^3x}{1+x^2}dx}_{u=x^2}-3K+R=\boxed{\frac{357}{64}\zeta(4)-3K+R}\\ \end{align*}
\begin{align*} D&\overset{IBP}=-\frac32\underbrace{\int_0^1\frac{\ln^2x\ln(1+x^2)}{(1+x)^2}dx}_{=H}-\frac12\underbrace{\int_0^1\frac{\ln^3x}{(1+x)^2}dx}_{\text{IBP}}-\frac32K+\\&\frac32\underbrace{\int_0^1\frac{\ln^2x\ln(1+x^2)}{x}dx}_{\text{IBP}}+\frac12R\\ &=-\frac32H+\frac32\int_0^1\frac{\ln^2x}{1+x}dx-\frac32K+\frac{21}{64}\zeta(4)+\frac12R\\ &=-\frac32H+\frac94\zeta(3)-\frac32K+\frac{21}{64}\zeta(4)+\frac12R\\ H&\overset{\text{IBP}}=-2\underbrace{\int_0^1\frac{\ln x\ln(1+x^2)}{1+x}dx}_{=L}-\int_0^1\frac{\ln^2x}{1+x}dx+2\underbrace{\int_0^1\frac{\ln(1+x^2)\ln x}{x}dx}_{\text{IBP}}+\\&\underbrace{\int_0^1\frac{x\ln^2x}{1+x^2}dx}_{u=x^2}+\underbrace{\int_0^1\frac{\ln^2x}{1+x^2}dx}_{=\frac{\pi^3}{16}}\\ &=-2L-\frac{27}{16}\zeta(3)+\frac{\pi^3}{16}\\ D&=3L+\frac{153}{32}\zeta(3)-\frac{3\pi^3}{32}-\frac32K+\frac{21}{64}\zeta(4)+\frac12R\\ 4D-2C&=12L+\frac{153}{8}\zeta(3)-\frac38\pi^3-\frac{315}{32}\zeta(4) \end{align*} \begin{align*}L&\overset{\text{IBP}}=\left[\left(\int_0^x\frac{\ln t}{1+t}dt\right)\ln(1+x^2)\right]_0^1-\int_0^1\int_0^1\frac{x\ln(tx)}{(1+tx)(1+x^2)}dtdx\\ &=-\frac{\pi^2\ln 2}{12}+2\int_0^1\int_0^1\frac{\ln(tx)-tx\ln(tx)}{(1+t^2)(1+x^2)}dtdx-2\int_0^1\int_0^1\frac{\ln(tx)}{(1+t^2)(1+tx)}dtdx\\ &=-\frac{\pi^2\ln 2}{12}+4\int_0^1\int_0^1\frac{\ln x}{(1+t^2)(1+x^2)}dtdx-4\int_0^1\int_0^1\frac{tx\ln x}{(1+t^2)(1+x^2)}dtdx-\\ &2\underbrace{\int_0^1\frac{1}{t(1+t^2)}\left(\int_0^t\frac{\ln x}{1+x}\right)}_{\text{IBP}}\\ &=-\frac{\pi^2\ln 2}{24}-\pi\text{G}-2\left[\Big(\ln t-\frac{1}{2}\ln(1+t^2)\Big)\int_0^t\frac{\ln x}{1+x}dx\right]_0^1+\\&2\int_0^1\frac{\Big(\ln t-\frac{1}{2}\ln(1+t^2)\Big)\ln t}{1+t}dx\\ &=-\frac{\pi^2\ln 2}{8}-\pi\text{G}+3\zeta(3)-L\\ &\boxed{L=-\frac{\pi^2\ln 2}{16}-\frac{\pi\text{G}}{2}+\frac{3\zeta(3)}2}\\ \end{align*} Since, \begin{align*} A=-\frac92\zeta(3),B=-\frac32\zeta(2)-\frac94\zeta(3),-8F+4E=3\pi^2-24\zeta(3) \end{align*} Therefore, \begin{align*} \boxed{I=\frac{105\zeta(3)}{8}-\frac{3\pi^3}{8}-\frac{7\pi^2\ln 2}{4}+3\pi^2-6\pi\text{G}-\frac{7\pi^4}{64}} \end{align*}

FDP
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\begin{align} I &= \int_0^1 \frac{2(x-1) \ln^3(x) \left[2 \ln(x+1) - \ln \left(2(x^2+1)\right)\right]}{(x+1)^3} \, dx \\ &= 4 \underbrace{\int_0^1 \frac{x \ln^3(x) \ln(1+x)}{(1+x)^3} \, dx}_{I_1} - 2 \underbrace{\int_0^1 \frac{x \ln^3(x) \ln \left(2(1+x^2)\right)}{(1+x)^3} \, dx}_{I_2} \\ &\quad - 4 \underbrace{\int_0^1 \frac{\ln^3(x) \ln(1+x)}{(1+x)^3} \, dx}_{I_3} + 2 \underbrace{\int_0^1 \frac{\ln^3(x) \ln \left(2(1+x^2)\right)}{(1+x)^3} \, dx}_{I_4} \end{align}

In this first part, the integral $I$ is split into four integrals labeled $I_1, I_2, I_3,$ and $I_4$, based on the terms in the integrand.

\begin{align} I_1 &= \text{Integration by parts} - \left.\frac{1}{2} \ln^3(x) \ln(1+x) \frac{2x+1}{(1+x)^2}\right|_0^1 \\ &\quad + \frac{1}{2} \int_0^1 \frac{2x+1}{(1+x)^2} \left(\frac{\ln^3(x)}{1+x} + \frac{3 \ln^2(x) \ln(1+x)}{x}\right) \, dx \\ &= \underbrace{\int_0^1 \frac{x \ln^3(x)}{(1+x)^3} \, dx}_{I_5} + 3 \underbrace{\int_0^1 \frac{\ln^2(x) \ln(1+x)}{(1+x)^2} \, dx}_{I_6} \\ &\quad + \frac{1}{2} \underbrace{\int_0^1 \frac{\ln^3(x)}{(1+x)^3} \, dx}_{I_7} + \frac{3}{2} \underbrace{\int_0^1 \frac{\ln^2(x) \ln(1+x)}{x(1+x)^2} \, dx}_{I_8} \end{align}

In this second part, the integral $I_1$ is computed using integration by parts, yielding expressions involving new integrals $I_5, I_6, I_7,$ and $I_8$.

\begin{align} I_5 &= \frac{1}{2} \sum_{n=2}^{\infty} (-1)^n n(n-1) \int_0^1 x^{n-1} \ln^3(x) \, dx \\ &= -3 \sum_{n=2}^{\infty} \frac{(-1)^n (n-1)}{n^3} \\ &= -3 \left(\sum_{n=1}^{\infty} \frac{(-1)^n}{n^2} - \sum_{n=1}^{\infty} \frac{(-1)^n}{n^3}\right) \\ &= 3 (\eta(2) - \eta(3)) \\ &= \frac{3}{2} \zeta(2) - \frac{9}{4} \end{align}

Here, the integral $I_5$ is evaluated using a series representation, resulting in terms involving the Dirichlet eta function $\eta(s)$ and the Riemann zeta function $\zeta(s)$.

\begin{align} I &= \text{Integration by parts} - \left.\frac{\ln^2(x) \ln(1+x)}{1+x}\right|_0^1 \\ &\quad + \int_0^1 \frac{\ln(x)}{1+x} \left(\frac{\ln(x)}{1+x} + \frac{2 \ln(1+x)}{x}\right) \, dx \\ &= \underbrace{\int_0^1 \frac{\ln^2(x)}{(1+x)^2} \, dx}_{I_9} + 2 \underbrace{\int_0^1 \frac{\ln(x) \ln(1+x)}{x(1+x)} \, dx}_{I_{10}} \\ I_9 &= -\sum_{n=1}^{\infty} (-1)^n n \int_0^1 x^{n-1} \ln^2(x) \, dx \\ &= 2 \sum_{n=1}^{\infty} \frac{(-1)^{n-1}}{n^2} \\ &= 2 \eta(2) \\ &= \zeta(2) \\ I_{10} &= -\sum_{n=1}^{\infty} (-1)^n H_n \int_0^1 x^{n-1} \ln(x) \, dx \\ &= \sum_{n=1}^{\infty} \frac{(-1)^n H_n}{n^2} \\ &= -\frac{5}{8} \zeta(3) \end{align}

In this final part, the integrals $I_9$ and $I_{10}£ are computed using series representations involving harmonic numbers and the Riemann zeta function.

\begin{align} I_8 &= \text{Integration by parts} \, \ln^2(x) \ln(1+x) \left[\frac{1}{1+x} + \ln \left(\frac{x}{1+x}\right)\right] \bigg|_0^1 \\   &\quad - \int_0^1 \left(\frac{1}{1+x} + \ln(x) - \ln(1+x)\right) \left(\frac{\ln^2(x)}{1+x} + \frac{2 \ln(x) \ln(1+x)}{x}\right) \, dx \\   &= - \underbrace{\int_0^1 \frac{\ln^2(x)}{(1+x)^2} \, dx}_{I_9} - 2 \underbrace{\int_0^1 \frac{\ln(x) \ln(1+x)}{x(1+x)} \, dx}_{I_{10}} - \underbrace{\int_0^1 \frac{\ln^3(x)}{1+x} \, dx}_{I_{11}} \end{align}

In this first part, $I_8$ is expressed as an integration by parts term minus a complex integral. The integral is split into terms labeled $I_9, I_{10},$ and $I_{11}$.

\begin{align} & - 2 \underbrace{\int_0^1 \frac{\ln^2(x) \ln(1+x)}{x} \, dx}_{I_{12}} + \underbrace{\int_0^1 \frac{\ln^2(x) \ln(1+x)}{1+x} \, dx}_{I_{13}} + 2 \underbrace{\int_0^1 \frac{\ln(x) \ln^2(1+x)}{x} \, dx}_{I_{14}} \\ I_{11} &= \sum_{n=0}^{\infty} (-1)^n \int_0^1 x^n \ln^3(x) \, dx \\   &= -6 \sum_{n=1}^{\infty} \frac{(-1)^{n-1}}{n^4} \\   &= -6 \eta(4) \\   &= -\frac{21}{4} \zeta(4) \quad \text{(using the relation between eta and zeta functions)} \end{align}

In this second part, integrals $I_{12}, I_{13},$ and $I_{14}$ are introduced. The integral $I_{11}$ is evaluated using series representations involving the eta function and zeta function.

\begin{align} I_{12} &= \text{Integration by parts} \, \ln^3(x) \ln(1+x) \bigg|_0^1 \\   &\quad - \int_0^1 \ln^2(x) \left(\frac{\ln(x)}{1+x} + \frac{2 \ln(1+x)}{x}\right) \, dx \\   &= -I_{11} - 2 I_{12} \\   &\Rightarrow I_{12} = -\frac{1}{3} I_{11} \\   &= \frac{7}{4} \zeta \quad \text{(substituting the value of } I_{11}) \end{align}

This third part evaluates $I_{12}$ using integration by parts and solves for $I_{12}$ in terms of $I_{11}$.

\begin{align} I_{13} &= \int_0^1 \frac{\ln^2(x) \ln(1+x)}{1+x} \, dx \\   &= -\sum_{n=1}^{\infty} (-1)^n H_n \int_0^1 x^n \ln^2(x) \, dx \\   &= 2 \sum_{n=1}^{\infty} \frac{(-1)^{n+1} \left(H_n - \frac{1}{n+1}\right)}{(n+1)^3} \\   &= 2 \left(\sum_{n=1}^{\infty} \frac{(-1)^n H_n}{n^3} + \eta(4)\right) \\   &= 4 \operatorname{Li}_4\left(\frac{1}{2}\right) - \ln^2(2) \zeta(2) \\   &\quad + \frac{7}{2} \ln(2) \zeta(3) + \frac{1}{6} \ln^4(2) - \frac{15}{4} \zeta(4) \quad \text{(evaluating using known series results)} \end{align}

In the final part, $I_{13}$ is computed using series representations and special functions like polylogarithms and logarithms.

\begin{align} & \text{Combining all results:} \\ & \Rightarrow I_8 = -4 \operatorname{Li}_4\left(\frac{1}{2}\right) + \ln^2(2) \zeta(2) - \frac{7}{2} \ln(2) \zeta(3) \\ & \quad - \frac{1}{6} \ln^4(2) + \frac{11}{2} \zeta(4) + \frac{5}{4} \zeta(3) - \zeta(2) \\ & \Rightarrow I_1 = -6 \operatorname{Li}_4\left(\frac{1}{2}\right) + \frac{3}{2} \ln^2(2) \zeta(2) \\ & \quad - \frac{21}{4} \ln(2) \zeta(3) - \frac{1}{4} \ln^4(2) \\ & \quad + \frac{33}{4} \zeta(4) - \frac{21}{4} \zeta(3) + \frac{9}{4} \zeta(2) \end{align}

In this concluding part, the final values of $I_8$ and $I_1$ are obtained by combining the results from the previous steps.

\begin{align} I_2 &= \ln(2) \underbrace{\int_0^1 \frac{x \ln^3(x)}{(1+x)^3} \, dx}_{I_5} + \underbrace{\int_0^1 \frac{x \ln^3(x) \ln \left(1+x^2\right)}{(1+x)^3} \, dx}_{I_{15}} \\ I_{15} &= \text{Integration by parts} \\   &\quad - \left. \frac{1}{2} \ln^3(x) \ln \left(1+x^2\right) \frac{2x+1}{(1+x)^2} \right|_0^1 \\   &\quad + \frac{1}{2} \int_0^1 \frac{2x+1}{(1+x)^2} \left(\frac{2x \ln^3(x)}{1+x^2} + \frac{3 \ln^2(x) \ln \left(1+x^2\right)}{x(1+x)^2}\right) \, dx \\   &= 2 \underbrace{\int_0^1 \frac{x^2 \ln^3(x)}{(1+x)^2 (1+x^2)} \, dx}_{I_{16}} \\   &\quad + 3 \underbrace{\int_0^1 \frac{\ln^2(x) \ln \left(1+x^2\right)}{(1+x)^2} \, dx}_{I_{17}} \\   &\quad + \underbrace{\int_0^1 \frac{x \ln^3(x)}{(1+x)^2 (1+x^2)} \, dx}_{I_{18}} \\   &\quad + \frac{3}{2} \underbrace{\int_0^1 \frac{\ln^2(x) \ln \left(1+x^2\right)}{x(1+x)^2} \, dx}_{I_{19}} \end{align}

In this first part, $I_2$ is broken into two integrals: $I_5$ and $I_{15}$. The integral $I_{15}$ is evaluated using integration by parts and separated into simpler integrals $I_{16}$ through $I_{19}$.

\begin{align} I_{16} &= \int_0^1 \frac{x^2 (1-x)^2 (1+x^2) \ln^3(x)}{(1-x^4)^2} \, dx \\   &= \int_0^1 \frac{\left(x^2 - 2x^3 + 2x^4 - 2x^5 + x^6\right) \ln^3(x)}{(1-x^4)^2} \, dx \\   &= \underbrace{\int_0^1 \frac{x^2 \ln^3(x)}{(1-x^4)^2} \, dx}_{I_{20}} \\   &\quad - 2 \underbrace{\int_0^1 \frac{x^3 \ln^3(x)}{(1-x^4)^2} \, dx}_{I_{21}} \\   &\quad + 2 \underbrace{\int_0^1 \frac{x^4 \ln^3(x)}{(1-x^4)^2} \, dx}_{I_{22}} \\   &\quad - 2 \underbrace{\int_0^1 \frac{x^5 \ln^3(x)}{(1-x^4)^2} \, dx}_{I_{23}} \\   &\quad + \underbrace{\int_0^1 \frac{x^6 \ln^3(x)}{(1-x^4)^2} \, dx}_{I_{24}} \end{align}

Here, $I_{16}$ is decomposed into simpler integrals $I_{20}$ through $I_{24}$.

\begin{align} I_{20} &= \sum_{n=1}^{\infty} n \int_0^1 x^{4n-2} \ln^3(x) \, dx \\   &= -\frac{3}{2} \sum_{n=1}^{\infty} \frac{(4n-1) + 1}{(4n-1)^4} \\   &= -\frac{3}{2} \left(\frac{1}{4^3} \sum_{n=1}^{\infty} \frac{1}{\left(n - \frac{1}{4}\right)^3} + \frac{1}{4^4} \sum_{n=1}^{\infty} \frac{1}{\left(n - \frac{1}{4}\right)^4}\right) \\   &= \frac{1}{1024} \psi_3 \left(\frac{1}{4}\right) - \frac{45}{32} \zeta(4) - \frac{21}{32} \zeta(3) + \frac{3 \pi^3}{128} \end{align}

In this part, $I_{20}$ is computed using series and special functions.

\begin{align} I_{21} &= \sum_{n=1}^{\infty} n \int_0^1 x^{4n-1} \ln^3(x) \, dx \\   &= -\frac{3}{128} \sum_{n=1}^{\infty} \frac{1}{n^3} \\   &= -\frac{3}{128} \zeta \end{align}

\begin{align} I_{22} &= \sum_{n=1}^{\infty} n \int_0^1 x^{4n} \ln^3(x) \, dx \\   &= -\frac{3}{2} \sum_{n=1}^{\infty} \frac{(4n+1) - 1}{(4n+1)^4} \\   &= -\frac{3}{2} \left(\frac{1}{4^3} \sum_{n=1}^{\infty} \frac{1}{\left(n + \frac{1}{4}\right)^3} - \frac{1}{4^4} \sum_{n=1}^{\infty} \frac{1}{\left(n + \frac{1}{4}\right)^4}\right) \\   &= \frac{1}{1024} \psi_3 \left(\frac{1}{4}\right) - \frac{21}{32} \zeta(3) - \frac{3 \pi^3}{128} \end{align}

In this final part, $I_{22}$ is also evaluated using series and special functions, leading to the same results as before. \begin{align*} I_{23} &= \sum_{n=1}^{\infty} n \int_0^1 x^{4n+1} \ln^3(x) \, dx = -\frac{3}{16} \sum_{n=1}^{\infty} \frac{(2n+1) - 1}{(2n+1)^4} \\ &= -\frac{3}{16} \left( \frac{1}{2^3} \sum_{n=1}^{\infty} \frac{1}{\left(n + \frac{1}{2}\right)^3} - \frac{1}{2^4} \sum_{n=1}^{\infty} \frac{1}{\left(n + \frac{1}{2}\right)^4} \right) \\ &= -\frac{3}{16} \left( -\frac{1}{2^3} \frac{\psi_2\left(\frac{3}{2}\right)}{2!} - \frac{1}{2^4} \frac{\psi_3\left(\frac{3}{2}\right)}{3!} \right) \\ &= \frac{3}{256} \left[\psi_2\left(\frac{1}{2}\right) + 16 \right] + \frac{1}{512} \left[\psi_3\left(\frac{1}{2}\right) - 96 \right] \\ &= \frac{3}{256} (-14 \zeta(3)) + \frac{1}{512} (90 \zeta(4)) \\ &= \frac{45}{256} \zeta(4) - \frac{21}{128} \zeta(3) \ldots(\vartheta) \end{align*}

\begin{align*} I_{24} &= \sum_{n=1}^{\infty} n \int_0^1 x^{4n+2} \ln^3(x) \, dx = -\frac{3}{2} \sum_{n=1}^{\infty} \frac{(4n+3) - 3}{(4n+3)^4} \\ &= -\frac{3}{2} \left( \frac{1}{4^3} \sum_{n=1}^{\infty} \frac{1}{\left(n + \frac{3}{4}\right)^3} - \frac{3}{4^4} \sum_{n=1}^{\infty} \frac{1}{\left(n + \frac{3}{4}\right)^4} \right) \\ &= -\frac{3}{2} \left( -\frac{1}{4^3} \frac{\psi_2\left(\frac{7}{4}\right)}{2!} - \frac{3}{4^4} \frac{\psi_3\left(\frac{7}{4}\right)}{3!} \right) \\ &= \frac{3}{256} \left[\psi_2\left(\frac{3}{4}\right) + \frac{128}{27} \right] + \frac{3}{1024} \left[\psi_3\left(\frac{3}{4}\right) - \frac{512}{27} \right] \\ &= \frac{3}{256} \left(2 \pi^3 - 56 \zeta(3)\right) + \frac{3}{1024} \left[1440 \zeta(4) - \psi_3\left(\frac{1}{4}\right)\right] \\ &= -\frac{3}{1024} \psi_3\left(\frac{1}{4}\right) + \frac{135}{32} \zeta(4) - \frac{21}{32} \zeta(3) + \frac{3 \pi^3}{128} \\ &*(\chi) \wedge (\omega) \wedge (\wp) \wedge (\vartheta) \wedge (\varkappa) \rightarrow (\phi) \Rightarrow I_{16} = \frac{315}{128} \zeta(4) - \frac{9}{4} \zeta(3) \ldots(\Delta) \end{align*}

\begin{align*} I_{17} &\stackrel{I \underline{\underline{B}} P}{ }-\left.\frac{\ln^2(x) \ln\left(1 + x^2\right)}{1 + x}\right|_0^1 + 2 \int_0^1 \frac{\ln(x)}{x(1 + x)}\left(\frac{x^2 \ln(x)}{1 + x^2} + \ln\left(1 + x^2\right)\right) \, dx \\ &= 2 \left( \underbrace{\int_0^1 \frac{x \ln^2(x)}{\left(1 + x^2\right)(1 + x)} \, dx}_{I_{25}} + \underbrace{\int_0^1 \frac{\ln(x) \ln\left(1 + x^2\right)}{x(1 + x)} \, dx}_{I_{26}} \right) \ldots(\varpi) \end{align*}

\begin{align*} I_{25} &= \int_0^1 \frac{x(1 - x) \ln^2(x)}{1 - x^4} \, dx = \sum_{n=0}^{\infty} \int_0^1\left(x^{4n+1} - x^{4n+2}\right) \ln^2(x) \, dx \\ &= 2 \sum_{n=0}^{\infty}\left(\frac{1}{(4n+2)^3} - \frac{1}{(4n+3)^3}\right) \\ &= \frac{1}{32} \left( \sum_{n=0}^{\infty} \frac{1}{\left(n + \frac{1}{2}\right)^3} - \sum_{n=0}^{\infty} \frac{1}{\left(n + \frac{3}{4}\right)^3} \right) \\ &= \frac{1}{32} \left( -\frac{\psi_2\left(\frac{1}{2}\right)}{2!} + \frac{\psi_2\left(\frac{3}{4}\right)}{2!} \right) \\ &= \frac{1}{64} \left[14 \zeta(3) + \left(2 \pi^3 - 56 \zeta(3)\right) \right] \\ &= -\frac{21}{32} \zeta(3) + \frac{\pi^3}{32} \quad \ldots(\varrho) \end{align*}

\begin{align*} I_{26} &= \int_0^1 \frac{(1 - x) \ln(x) \ln\left(1 + x^2\right)}{x\left(1 - x^2\right)} \, dx = \sum_{n=1}^{\infty} \bar{H}_n \int_0^1 x^{2n-1}(1 - x) \ln(x) \, dx \\ &= \sum_{n=1}^{\infty} \bar{H}_n\left(-\frac{1}{(2n)^2} + \frac{1}{(2n+1)^2}\right) \\ &= \sum_{n=1}^{\infty} \frac{\bar{H}_n}{(2n+1)^2} - \frac{1}{4} \sum_{n=1}^{\infty} \frac{\bar{H}_n}{n^2} \\ &= \frac{\pi}{2} G + \frac{3}{4} \ln(2) \zeta(2) - \frac{7}{4} \zeta(3) - \frac{1}{4}\left(\frac{3}{2} \ln(2) \zeta(2) - \frac{1}{4} \zeta(3)\right) \\ &= \frac{3}{8} \ln(2) \zeta(2) - \frac{27}{16} \zeta(3) + \frac{\pi}{2} G \quad \ldots(\varsigma) \end{align*}

\begin{align*} &*(\varrho) \wedge (\varsigma) \rightarrow (\varpi) \Rightarrow I_{17} = \frac{3}{4} \ln(2) \zeta(2) - \frac{75}{16} \zeta(3) + \frac{\pi^3 }{16} + \pi G \ldots(\varphi) \end{align*}

\begin{align*} I_{18} &= \int_0^1 \frac{x(1-x)^2\left(1+x^2\right) \ln^3(x)}{\left(1-x^4\right)^2} \, dx \\ &= \int_0^1 \frac{\left(x - 2x^2 + 2x^3 - 2x^4 + x^5\right) \ln^3(x)}{\left(1-x^4\right)^2} \, dx \\ &= I_{27} - 2I_{20} + 2I_{21} - 2I_{22} + I_{23} \quad \ldots(\Lambda) \end{align*}

\begin{align*} I_{27} &= \int_0^1 \frac{x \ln^3(x)}{\left(1-x^4\right)^2} \, dx \\ &= \sum_{n=1}^{\infty} n \int_0^1 x^{4n-3} \ln^3(x) \, dx \\ &= -\frac{3}{16} \sum_{n=1}^{\infty} \frac{(2n-1)+1}{(2n-1)^4} \\ &= -\frac{3}{16} \left( \frac{1}{2^3} \sum_{n=1}^{\infty} \frac{1}{\left(n-\frac{1}{2}\right)^3}  + \frac{1}{2^4} \sum_{n=1}^{\infty} \frac{1}{\left(n-\frac{1}{2}\right)^4} \right) \\ &= -\frac{3}{16} \left( -\frac{1}{2^3} \frac{\psi_2\left(\frac{1}{2}\right)}{2!}  + \frac{1}{2^4} \frac{\psi_3\left(\frac{1}{2}\right)}{3!} \right) \\ &= \frac{3}{256} (-14 \zeta(3)) - \frac{1}{512} (90 \zeta(4)) \\ &= -\frac{45}{256} \zeta(4) - \frac{21}{128} \zeta(3) \quad \ldots(\Xi) \end{align*}

\begin{align*} I_{19} &\stackrel{IBP}{=} \left.\ln^2(x) \ln\left(1+x^2\right) \left[\frac{1}{1+x} + \ln\left(\frac{x}{1+x}\right)\right]\right|_0^1 \\ &\quad - 2 \int_0^1 \left(\frac{1}{1+x} + \ln(x) - \ln(1+x)\right) \frac{\ln(x)}{x}  \left(\frac{x^2 \ln(x)}{1+x^2} + \ln\left(1+x^2\right)\right) \, dx \\ &= -2 \Bigg(\underbrace{\int_0^1 \frac{x \ln^2(x)}{\left(1+x^2\right)(1+x)} \, dx}_{I_{25}}  + \underbrace{\int_0^1 \frac{x \ln^3(x)}{1+x^2} \, dx}_{I_{28}} \\ &\quad - \underbrace{\int_0^1 \frac{x \ln^2(x) \ln(1+x)}{1+x^2} \, dx}_{I_{29}}  + \underbrace{\int_0^1 \frac{\ln(x) \ln\left(1+x^2\right)}{x(1+x)} \, dx}_{I_{26}} \\ &\quad + \underbrace{\int_0^1 \frac{\ln^2(x) \ln\left(1+x^2\right)}{x} \, dx}_{I_{30}}  - \underbrace{\int_0^1 \frac{\ln(x) \ln(1+x) \ln\left(1+x^2\right)}{x} \, dx}_{I_{31}} \Bigg) \end{align*}

\begin{align*} I_{28} &= \sum_{n=0}^{\infty} (-1)^n \int_0^1 x^{2n+1} \ln^3(x) \, dx \\ &= -6 \sum_{n=0}^{\infty} \frac{(-1)^n}{(2n+2)^4} \\ &= -\frac{3}{8} \sum_{n=1}^{\infty} \frac{(-1)^{n-1}}{n^4} = -\frac{3}{8} \eta(4) \end{align*}

\begin{align*} I_{29} &\stackrel{IBP}{=} \frac{1}{2} \left.\ln^2(x) \ln(1+x) \ln\left(1+x^2\right)\right|_0^1 \\ &\quad - \frac{1}{2} \int_0^1 \ln\left(1+x^2\right) \left(\frac{\ln^2(x)}{1+x}  + \frac{2 \ln(x) \ln(1+x)}{x}\right) \, dx \\ &= -\frac{1}{2} \underbrace{\int_0^1 \frac{\ln^2(x) \ln\left(1+x^2\right)}{1+x} \, dx}_{I_{32}} - I_{31} \quad \ldots(\Theta) \end{align*}

\begin{align*} I_{32} &= \int_0^1 \frac{(1-x) \ln^2(x) \ln\left(1+x^2\right)}{1-x^2} \, dx \\ &= \sum_{n=1}^{\infty} \bar{H}_n \int_0^1 x^{2n}(1-x) \ln^2(x) \, dx \\ &= 2 \sum_{n=1}^{\infty} \bar{H}_n \left(\frac{1}{(2n+1)^3} - \frac{1}{(2n+2)^3}\right) \\ &= 2 \sum_{n=1}^{\infty} \frac{\bar{H}_n}{(2n+1)^3}  - \frac{1}{4} \sum_{n=1}^{\infty} \frac{\bar{H}_{n+1} - \frac{(-1)^n}{n+1}}{(n+1)^3} \\ &= 2 \sum_{n=1}^{\infty} \frac{\bar{H}_n}{(2n+1)^3}  - \frac{1}{4} \left(\sum_{n=1}^{\infty} \frac{\bar{H}_n}{n^3}  - \sum_{n=1}^{\infty} \frac{(-1)^{n-1}}{n^4}\right) \\ &= 2 \left(\frac{7}{8} \ln(2) \zeta(3) - \frac{45}{32} \zeta(4) + G^2\right)  - \frac{1}{4} \left(\frac{7}{4} \ln(2) \zeta(3) - \frac{5}{16} \zeta(4) - \eta(4)\right) \\ &= \frac{21}{16} \ln(2) \zeta(3) - \frac{161}{64} \zeta(4) + 2G^2 \end{align*}

\begin{align*} &*(\Xi) \rightarrow (\Theta) \Rightarrow I_{29} = -\frac{21}{32} \ln(2) \zeta(3)  + \frac{161}{128} \zeta(4) - G^2 - I_{31} \quad \ldots(\Phi) \end{align*}

\begin{align*} & \left. I_{30} \stackrel{IBP}{=} \ln^3(x) \ln\left(1+x^2\right) \right|_0^1  - 2 \int_0^1 \frac{\ln^2(x)}{x} \left(\frac{x^2 \ln(x)}{1+x^2} + \ln\left(1+x^2\right)\right) \, dx \\ & = -2 \left(\underbrace{\int_0^1 \frac{x \ln^3(x)}{1+x^2} \, dx}_{I_{28}}  + \underbrace{\int_0^1 \frac{\ln^2(x) \ln\left(1+x^2\right)}{x} \, dx}_{I_{30}}\right) \\ & \Rightarrow I_{30} = -\frac{2}{3} I_{28} = \frac{7}{32} \zeta(4) \end{align*}

\begin{align*} & *(\varrho) \wedge (\Psi) \wedge (\Phi) \wedge (\varsigma) \wedge (\Psi) \rightarrow (\Phi): \\ & \Rightarrow I_{19} = -\frac{21}{16} \ln(2) \zeta(3) - \frac{3}{4} \ln(2) \zeta(2)  + \frac{175}{64} \zeta(4) + \frac{75}{16} \zeta(3) - \frac{\pi^3}{16} - 2G^2 - \pi G \ldots \end{align*}

\begin{align*} & *(\Delta) \wedge (\varphi) \wedge (\Upsilon) \wedge (\Lambda) \rightarrow (v): \\ & \Rightarrow I_{15} = -\frac{1}{256} \psi_3\left(\frac{1}{4}\right) - \frac{63}{32} \ln(2) \zeta(3)  + \frac{9}{8} \ln(2) \zeta(2) + \frac{1515}{128} \zeta(4) - \frac{297}{32} \zeta(3) \\ & \quad + \frac{3\pi^3}{32} - 3G^2 + \frac{3\pi}{2} G \end{align*}

\begin{align*} & *(\gamma) \wedge (\Gamma) \rightarrow (\tau): \\ & \Rightarrow I_2 = -\frac{1}{256} \psi_3\left(\frac{1}{4}\right) - \frac{135}{32} \ln(2) \zeta(3)  + \frac{21}{8} \ln(2) \zeta(2) + \frac{1515}{128} \zeta(4) - \frac{297}{32} \zeta(3) \\ & \quad + \frac{3\pi^3}{32} - 3G^2 + \frac{3\pi}{2} G \end{align*}

\begin{align*} & I_3^I \underline{BP} - \left.\frac{1}{2} \frac{\ln^3(x) \ln(1+x)}{(1+x)^2}\right|_0^1  + \frac{1}{2} \int_0^1 \frac{\ln^2(x)}{(1+x)^2} \left(\frac{\ln(x)}{1+x} + \frac{3 \ln(1+x)}{x}\right) \, dx \\ & = \frac{1}{2} \underbrace{\int_0^1 \frac{\ln^3(x)}{(1+x)^3} \, dx}_{I_7}  + \frac{3}{2} \underbrace{\int_0^1 \frac{\ln^2(x) \ln(1+x)}{x(1+x)^2} \, dx}_{I_8} \end{align*}

\begin{align*} & *(\kappa) \wedge (\rho) \rightarrow (\Gamma): \\ & \Rightarrow I_3 = -6 \text{Li}_4\left(\frac{1}{2}\right) + \frac{3}{2} \ln^2(2) \zeta(2)  - \frac{21}{4} \ln(2) \zeta(3) - \frac{1}{4} \ln^4(2) + \frac{33}{4} \zeta(4) \\ & \quad + \frac{3}{4} \zeta(3) - \frac{9}{4} \zeta(2) \ldots (\aleph) \end{align*}

\begin{align*} & I_4 = \ln(2) \underbrace{\int_0^1 \frac{\ln^3(x)}{(1+x)^3} \, dx}_{I_7}  + \underbrace{\int_0^1 \frac{\ln^3(x) \ln\left(1+x^2\right)}{(1+x)^3} \, dx}_{I_{33}} \end{align*}

\begin{align*} & \left. I_{33} \underline{IP} \frac{\ln^3(x) \ln\left(1+x^2\right)}{2(1+x)^2} \right|_0^1  + \frac{1}{2} \int_0^1 \frac{1}{(1+x)^2} \left(\frac{2x \ln^3(x)}{1+x^2}  + \frac{3 \ln^2(x) \ln\left(1+x^2\right)}{x}\right) \, dx \\ & = \underbrace{\int_0^1 \frac{x \ln^3(x)}{(1+x)^2\left(1+x^2\right)} \, dx}_{I_{18}}  + \frac{3}{2} \underbrace{\int_0^1 \frac{\ln^2(x) \ln\left(1+x^2\right)}{x(1+x)^2} \, dx}_{I_{19}} \end{align*}

\begin{align*} & *(\Upsilon) \wedge (\Lambda) \rightarrow (\mathrm{O}): \\ & \Rightarrow I_{33} = -\frac{1}{256} \psi_3\left(\frac{1}{4}\right) - \frac{63}{32} \ln(2) \zeta(3)  - \frac{9}{8} \ln(2) \zeta(2) + \frac{885}{128} \zeta(4) + \frac{297}{32} \zeta(3) \\ & \quad - \frac{3\pi^3}{32} - 3G^2 - \frac{3\pi}{2} G \ldots \end{align*}

\begin{align*} & *(\kappa) \wedge (\Omega) \rightarrow (\Sigma): \\ & \Rightarrow I_4 = -\frac{1}{256} \psi_3\left(\frac{1}{4}\right) - \frac{135}{32} \ln(2) \zeta(3)  - \frac{21}{8} \ln(2) \zeta(2) + \frac{885}{128} \zeta(4) + \frac{297}{32} \zeta(3) \\ & \quad - \frac{3\pi^3}{32} - 3G^2 - \frac{3\pi}{2} G \end{align*}

\begin{align*} & * \text{Finally} (\sigma) \wedge (\Pi) \wedge (\aleph) \wedge (\Omega) \rightarrow (\alpha): \\ & \therefore I = -\frac{21}{2} \ln(2) \zeta(2) - \frac{315}{32} \zeta(4)  + \frac{105}{8} \zeta(3) + 18 \zeta(2) - \frac{3\pi^3}{8} - 6\pi G \end{align*}