Okay I'm really confused with continuous charge distributions, so I'm totally stuck... A continuous line of charge lies along the x axis, extending from x=+x_0 to positive infinity. The line carries a uniform linear charge density lambda_0. What are the magnitude and direction of the electric field at the origin? I have no idea where to approach or how to setup this problem up really.. What I tried to do is this.. Since, lambda = Q / L = dq / dx E = int dE = int k_e dq / r^2 = k_e int lambda dx / x^2 And then I'm completely stuck.... Do I need to find lambda or just integrate? or...? Any help is greatly appreciated. Thanks.