2,050 reputation
418
bio website qoqosz.net
location Poland
age 25
visits member for 2 years, 1 month
seen Jul 4 at 6:37

I'm just a physics student.


Jul
2
awarded  Curious
May
17
awarded  Yearling
Feb
16
answered Definite integral involving arctan and tan
Nov
6
comment A closed form for the sum $\sum_{n=1}^{\infty}\left(\frac{H_n}{n}\right)^2$
Check this one: ams.org/journals/proc/1995-123-04/S0002-9939-1995-1231029-X/…
Nov
6
comment Integral $\int_{-\infty}^{\infty}\frac{\mathrm dx}{(ax^2+2bx+c)^{\alpha}}$
It's one of the Beta function (en.wikipedia.org/wiki/Beta_function) representations. If you substitute $p = u^2$ it will become more apparent.
Nov
5
revised Evaluating $\lim\limits_{n \to \infty} (\int _a^b|f(x)|^ndx)^\frac 1n=\max\limits_{x\in[a,b]}|f(x)|$
added 17 characters in body
Nov
5
comment evaluation of $\int\frac{x^2}{\left(1+x^4\right)\sqrt{1+x^4}}dx$
If you are looking for an elementary solution - there isn't one due to: encyclopediaofmath.org/index.php/…
Nov
5
comment Integral from zero to infinity of $\int_0^{\infty}\frac{(1-e^{-\lambda z})}{\lambda^{a+1}} d \lambda$
@ghiasi This condition appears when you check when $\int_0^z t^{a-1} dt$ and $\int_0^{+\infty} x^{-a} e^{-x} dx$ converge ($z > 0$).
Nov
4
answered Evaluating $\lim\limits_{n \to \infty} (\int _a^b|f(x)|^ndx)^\frac 1n=\max\limits_{x\in[a,b]}|f(x)|$
Nov
4
answered Integral from zero to infinity of $\int_0^{\infty}\frac{(1-e^{-\lambda z})}{\lambda^{a+1}} d \lambda$
Nov
4
answered Show that if $x>0$, then $\ln(x)\geq 1-\frac{1}{x} $
Nov
2
comment Integration in n-spherical coordinates
Thanks, I've already got an answer on physics.SE: physics.stackexchange.com/questions/83103/…
Oct
31
asked Integration in n-spherical coordinates
Oct
13
comment Divergence in spherical coordinates
@user8268 So if $\vec F$ is defined as: $F^\alpha = \frac{\partial f (u(r, \theta, \phi), \ldots)}{\partial (\nabla_\alpha u)}$ and I compute $\nabla_\alpha u$ as $(\partial_r u, \frac{1}{r} \partial_\theta u, \frac{1}{r \sin \theta} \partial_\phi u)$ than which formula for $\nabla \cdot \vec{F}$ should I use? The first one?
Oct
13
asked Divergence in spherical coordinates
Aug
9
awarded  Necromancer
Jun
26
comment Solving the integral $\int_{0}^{\infty} \frac{\sin{x}}{x} \ dx = \frac{\pi}{2}$?
@André indeed, thanks.
Jun
26
revised Solving the integral $\int_{0}^{\infty} \frac{\sin{x}}{x} \ dx = \frac{\pi}{2}$?
fixed typo
May
24
comment Improper integral and special functions
@RaymondManzoni thank you.
May
24
accepted Improper integral and special functions