Simple question on renormalization

[moriheru]

This is a ambarassingly simple question, the question is if my explantion is acceptable. I have come across the integrant form negative infinity to positive infinity and I have come across the integrand from 2pi to zero that is set equal to 1 and then abs value squared of the wavefunction and so on, this is all clear to me.
My explanation concernes the 2pi zero integrand, does one use this (2pi zero) because one is talking about a circular area?

Thanks, for clarifications

 

[Einj]

In depends on what's the variable integrated from 0 to $2\pi$. If it's something like the azimuthal angle, then $[0,2\pi)$ is simply the full domain.

 

[moriheru]

Yes something will angles. I guess my assumption is correct then if it concernes angles. Thankyou EInji