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21h
reviewed Approve suggested edit on Does a solution to the differential equation $y'=y$ exist?
23h
reviewed Approve suggested edit on show a set is lebesgue measurable
1d
awarded  Custodian
1d
reviewed Approve suggested edit on poincare-bendixson theorem contradiction
1d
answered Solid of revolution vs $\iiint$
1d
comment How to find $\nabla$ in spherical coordinates
I'd have thought that $x=r\sin \theta \cos\phi, y= r \sin \theta \sin \phi, z=r \cos \theta$ and the chain rule for partial derivatives is enough (though messy).
1d
answered fourier series, parsevel's identity
1d
awarded  Organizer
1d
revised Solving integral $ \int \frac{x+\sqrt{1+x+x^2}}{1+x+\sqrt{1+x+x^2}}\:\mathrm{d}x $
It's really nothing to do with irrationals.
1d
suggested suggested edit on Solving integral $ \int \frac{x+\sqrt{1+x+x^2}}{1+x+\sqrt{1+x+x^2}}\:\mathrm{d}x $
1d
comment Integral $I=\int_0^\infty \frac{x^4}{(\alpha+x^2)^4}dx$
@Integrals Substitute $t=u^2$, and use $$B(x,y)=\int_0^\infty \frac{t^{x-1}}{(1+t)^{x+y}}dx,$$ where $B(x,y)= \frac{\Gamma(x) \Gamma(y)}{\Gamma(x+y)}$ is the beta function.
2d
awarded  Talkative
2d
comment How to convert a integral into the another?
@Victor An excellent explanation is here.
2d
comment Closed form for $\int_0^1 \frac{x^a dx}{(1+x^b)^c}$.
This is essentially what the other answers do, the equivalence between their forms and your idea basically comes from the definition of the hypergeometric function.
2d
comment Which $n$th order differential equations have $n$ linearly independent solutions?
Thanks. However, you seem to have just proven the case for $n=2$, not general $n$ (or, indeed, for other types of differential equation).
2d
comment Different methods to prove $\zeta(s)=2^s\pi^{s-1}\sin\left(\frac{s\pi}{2}\right) \Gamma (1-s) \zeta (1-s)$.
@AlexB. I've encountered a few things that need $p$-adic numbers, but never a particularly good introduction on them. I know this is not really to do with the original question, but do you know of a good introduction? Regardless, thanks for the speedy response.
2d
comment Different methods to prove $\zeta(s)=2^s\pi^{s-1}\sin\left(\frac{s\pi}{2}\right) \Gamma (1-s) \zeta (1-s)$.
@AlexB. What theory is necessary to understand Tate's proof?
2d
revised A question on convergence of Fourier series and the derivative of the function
Fixed LaTeX
2d
suggested suggested edit on A question on convergence of Fourier series and the derivative of the function
2d
revised Integrate $I=\int_0^1\frac{\ln x}{x^n-1}dx$
added 504 characters in body