I just recently began the Electricity and Magnetism course. Having said that I'm requesting help with a general plan of attack for two homework problems, that is, conceptually understanding how to use the math on these problems. First problems states there is a hollow cylinder of length h and radius R, determine the electric feild at point d to the right of the cylinder (this is the axis through the center). It also states to think of the cylinder as a collection of rings and gives me nearly the same problem solved for a single ring. My question is how would I adapt the results of the ring? My second problem is a uniformly charged disk of radius R and charge Q. This also has the electric feild calculated along the axis through the disk. The problem asks show that the electric feild at distances x that are large compared with R approaches that of a point charge. How would I go about grappling this problem? What I'm essentially asking is a gameplan for these problems like, do I integrate and if so along what axis. Thanks for any help you can give me.