Integral Calculation: Solving Complex Integrals with Unknown Constants

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Homework Statement


Calculate the integral:

\int x \frac{dx}{\sqrt{(a^2+x^2)^3}}

where a\in R

Homework Equations





The Attempt at a Solution


I solved "similar" integrals like \int \frac{dx}{\sqrt{a^2+x^2}}

and \int \frac{dx}{x(x^2+1)}

but none of the approaches I know (and used for the above) seem to work. Not sure how to start here. Any ideas?
 
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Just try substituting u=x^2+a^2. Your integral is even easier than the other two.
 
Yes, it was. I was making a silly mistake.

Thanks!
 
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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