2011-02-06, 11:45 AM
The problem with evaluating that function on a region different than the whole (x,y) plane is that it will generally lead to something difficult to describe in polar coordinates (r,theta) which in turn lead to an integral that you cannot separate in two independent ones (one in r, one in theta).
The way you do it, you pass from a section (or the whole) x axis to a symetrical thing in 2D, which will most likely be in the form of a rectangle, which is hard to describe in polar.
The way you do it, you pass from a section (or the whole) x axis to a symetrical thing in 2D, which will most likely be in the form of a rectangle, which is hard to describe in polar.