\newcommand{\arctanh}{~\mathrm{arctanh}~}\newcommand{\sech}{~\mathrm{sech}~}
I=\int_{-1}^1\frac{\arctan x}{\arctanh x}\,\mathrm{d}x
Mathematica gives an approximate result of I=1.581949621806183890451628..., but no exact form. I predict it's a function of e and \pi, and perhaps even the Golden Ratio \phi (It certainly wouldn't be the first time)
The motivation behind this question is pure curiosity. I thought the shape looked nice :)
1st edit: Substitutions of x=\tan u and x=\tanh u respectively yield
I= 2\int_{-\pi/4}^{\pi/4}\dfrac{u\sec^2u}{\ln|\frac{1+\tan u}{1-\tan u}|}\,\mathrm{d}u
I= \int_{-\infty}^{\infty}\dfrac{\arctan(\tanh u)}{u}\sech^2u\,\mathrm{d}u
2nd edit: I've considered another approach starting with parameterizing the desired integral by
I_a=\int_{-1}^1\frac{\arctan ax}{\arctanh x}\,\mathrm{d}x
so that
\frac{\partial I_a}{\partial a}=\int_{-1}^1\frac{x}{(1+(ax)^2)\arctanh x}\,\mathrm{d}x
Integrating by parts with
\begin{matrix}u=\dfrac{1}{\arctanh x}&&\mathrm{d}v=\dfrac{x}{1+(ax)^2}\,\mathrm{d}x\\[1ex] \mathrm{d}u=\dfrac{\mathrm{d}x}{(x^2-1)\arctanh^2x}&&v=\dfrac{1}{2a^2}\log(1+(ax)^2)\end{matrix}
yields the following integral:
\frac{\partial I_a}{\partial a}=\frac{1}{2a^2}\int_{-1}^1\frac{\log(1+(ax)^2)}{(1-x^2)\arctanh^2x}\,\mathrm{d}x
which can be modified by a substitution of y=\arctanh x to obtain
\frac{\partial I_a}{\partial a}=\frac{1}{2a^2}\int_{-\infty}^\infty \frac{\log(1+(a\tanh y)^2)}{y^2}\,\mathrm{d}y
I have an idea of approaching the remaining integral using the series expansion of \log(1+x); namely, the integral would become
\frac{\partial I_a}{\partial a}=\frac{1}{2a^2}\int_{-\infty}^\infty \frac{\mathrm{d}y}{y^2}\sum_{k=1}^\infty\frac{(-1)^{k+1}}{k}(a\tanh y)^{2k}=-\frac{1}{2a^2}\sum_{k=1}^\infty \frac{a^{2k}(-1)^k}{k}\underbrace{\int_{-\infty}^\infty \frac{\tanh^{2k}y}{y^2}\,\mathrm{d}y}_{J_k}
According to this question, we have a closed from J_k in the case of k=1 and potentially all k>1 in terms of the Riemann zeta function, but I have yet to do any more investigation.
Another method that occurred to me was to consider a keyhole contour to tackle \dfrac{\partial I_a}{\partial a} but I'm afraid I'm not familiar enough with complex analysis to make that jump just yet.
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