Integral of (ln(e^x + 1))^(1/3) / (e^x + 1)

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ravenea said:

Homework Statement



Integral of (ln(e^x + 1))^(1/3) / (e^x + 1)
See http://www2.wolframalpha.com/input/?i=integral+of+(ln(e**x+++1))**(1/3)/(e**x+++1)"


Homework Equations



N/A

The Attempt at a Solution



First, substitute k = ln(e^x + 1) dk = dx(e^x)/(e^x + 1)
Then, used integration by parts, but got to a loop...

If you let u = ln(ex+1) show us what you get for your du integral. There should be no x's in it.
 
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Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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