I'm trying to calculate the electric field due to a hollow cylinder. The cylinder is "semi infinite" with one end at x=0 and the other at - infinity, and radius R. I'm trying to calculate the field at a point x along the axis (not above the end of the cylinder). The cylinder has charge density sigma (the problem specifically states to use surface charge density instead of line charge). Am I correct in assuming that the radial field cancels? I can't figure out how to set this problem up. I'm also supposed to calculate the field at x=0, at the "surface" of cylinder. Is this point inside the cylinder with E =0, or no? Any help would be much appreciated, thanks!