1. Problem statement. 2. Known equations. E = k § dq/r^2 Lamda = Q/L 3. Attempt. I am having trouble figuring out the dq in this situation. I know that lamda = Q/L, and since those 2 are the variables that are changing I take the derivative of them so it looks like Lamda = dq/dL I solve for dq giving me dq = lamda * dL Which is where I am stuck. When I enter the new dq into the integral for the electric field, I do not know what to use for the r^2, I am aware that L=R(theta) but I am having trouble being able to manipulate R in terms of L since the only way is having a theta into the integral, but I cant integrate it because the bounds are going to be the length of the rod.. Any input is much appreciated, thanks!