Hello, I know you can use Gauss' law to calculate the electric field of volume and surface charges but i cannot figure out a way to do it using Coloumb's law. I have several questions about this: when you integrate the charge density in Coloumb's law over the volume is the r^2 inside or outside the integral? is the unit vector necessary to calculate within the integral or is it allowed to drop the unit vector and obtain a scalar equation for the electric field's magnitude? Lastly, when I calculate the electric field of volume charges, i notice that after I integrate, I lose spatial coordinates with which to calculate the electric field at certain points in space. I am sorry for the long post but I have been struggling with this for sometime.