Recent content by azoroth134

I already did that, I just don't know what to do after that, I don't have any derivative to perform on x or p

Hi, I wish to get position operator in momentum space using Fourier transformation, if I simply start from here, $$ <x>=\int_{-\infty}^{\infty} dx \Psi^* x \Psi $$ I could do the same with the momentum operator, because I had a derivative acting on |psi there, but in this case, How may I get...

problem solved, thanks a lot

Ah great, thank you very much, I almost got it on the track now, this is $$ \int_{0}^{\infty} x^3 e^{-(n+1)x} dx = 6 (n+1)^{-4}$$ can you just tell me a little about how to evaluate the summation of $$\sum \frac{1}{(n+1)^4}$$ though, I think I forgot this evaluation. thanks in advance

Homework Statement HI people, I was trying to derive the stefan-boltzman law from the planc's formula, I kind of got stuck with an integral Homework Equations $$ \int_{0}^{\infty} \frac{x^3}{e^x -1} dx $$ The Attempt at a Solution I tried simplifying it with $$ \int_{0}^{\infty} x^3...