Two positive point charges each have a charge of +q and are fixed on the y axis at y = +a and y = -a. (Use k, q, a, and x as necessary.) (a) Find the electric potential at any point on the x axis. V = 2kq/[sqrt(x^2+a^2)] (b) Use your result in part (a) to find the electric field at any point on the x axis. For part B, would I differentiate the potential with respect to x? If so, my answer would be (-2xkq)/[(x^2+a^2)^(3/2)] If you can please, I'm also having trouble understanding why the electric field is the derivative of the potential with respect to its distance..