What are the boundaries of tetha?

[asi123]

Homework Statement

I need to find the circulation of F through L.
I tried to use Gauss' law to find it, so I first found the divergence and so on.
Anyway, somewhere in the solution I switch to polar coordinate system but I didn't changed z, what means I took the boundaries of z from r to 2-r^2 as you can see in the attach.
My question is, can I do that or do I need to change to spherical coordinate system? and if so, what are the boundaries of tetha?

Homework Equations

The Attempt at a Solution

 

[Defennder]

I got zero as well. I think's fine to do in cylindrical coordinates.

 

[asi123]

I got zero as well. I think's fine to do in cylindrical coordinates.

Ok, thanks.

 

[Defennder]

Um, what do you mean by Gauss law? Do you have any reason to believe that F denotes a conservative electric field?

 

[asi123]

Um, what do you mean by Gauss law? Do you have any reason to believe that F denotes a conservative electric field?

I think u got mistaken in the trades again

 

[Defennder]

Not this time :) Your first post above said something about Gauss law.