Recent content by ntusg

Thank you, Ygggdrasil! I just got the same answer from other friends ...

I encountered a chemical (COOEt)2C, and I don't really know what does Et mean. I am not familiar with chemistry, but I guess this is something similar to -R which stands for -CH3, -CH2CH3 etc. Could anyone help to explain? Thanks you very much.

Hi Dick, I just got it, and it only about rewriting dV in Cartesian to the polar coordinate. Thanks for the help!

Homework Statement During my calculation of hydrogen atom perturbation, I need to integral below in cartesian coordinate. It is given that below integral can be transformed. Homework Equations Anyone could help to see what will the transformed integral in polar coordinate if the...

"Group velocity (equal to an electron's speed) should not be confused with phase velocity (equal to the product of the electron's frequency multiplied by its wavelength)." Above statement is from wikipedia, and I still don't quite understand it. As one of the postulate of QM, group velocity...