Hello, It has a been a while since college let alone since I've done any serious calculus, so I hope you can help explain this integral in a simple way that I can understand: refer to the attached figure. I am trying to find the integral of z dV where dV is increment of volume. which could be written as integral of z dx dy dz now I am trying to understand how to integrate z over dx and dy. the integral will be a circle of a certain radius but how do we exactly integrate z over dx and over dy ? please no spherical/cylindrical coordinates. thanks a lot.