1. The problem statement, all variables and given/known data Part a. A cylinder (with no face) is centered symmetrically around the z axis, going from the origin to infinity. It has charge density σ and radius R. Find the electric field at the origin. Part b. Same problem, except this time instead of a hollow cylinder with no face we have a solid cylinder. It also now has charge density ρ. Find the electric field at the origin. 2. Relevant equations Ering = kQz/(z2+ R2)3/2 σ =dq/2πRdz Edisk = σ/2εo * (1 - z/(z2+R2)1/2) ρ =dq/πR2dz 3. The attempt at a solution I understand that to complete part a I must integrate the electric field of a charged ring (a distance z from its center) from z = 0 to z = ∞. I understand that to complete part b I must integrate the electric field of a charged disk (a distance z from its center) from z = 0 to z = ∞. Here is my solution to part a (I'm not sure if it's correct): EHollow Cylinder = ∫0∞ kQz/(z2+ R2)3/2 dz = kσ2π/R I don't know how to set up the integral for part b. When I integrate the equation for Edisk, with a dz tacked onto the end (not so sure about this), I get undefined. Is this a part of the problem, or is my math incorrect?