1. The problem statement, all variables and given/known data A non-uniform surface charge lies in the xz-plane. At the origin, the surface charge density is (sigma)=3.01C/m^2; other charges are present in the vicinity as well. Just to the right of the origin the y-component of the electric field is 520,000N/C. What is the y-component of the electric field just to the left of the origin. Answer must take into account direction of field (left negative, right positive). 2. Relevant equations Gauss' Law, Coulomb's law, etc. I have the list of all of these, the problem is I just have no idea where to start with this. 3. The attempt at a solution No idea what to do.