1. The problem statement, all variables and given/known data Determine both the location and the maximum magnitude Emax of the electric field along the axis of a uniformly charged ring. (Use epsilon_0 for ε0, Q, and a as necessary.) 2. Relevant equations 1) dE= (ke)dq/r^2cos(theta) cos(theta)= x/r 2) Ex=Q*((ke*(x))/(a^2 + x^2)^3/2) (a is the radius of the ring) 3. The attempt at a solution I took the derivative of Equation 2 and set it equal to 0 to find the maximum x value x=(a*sqrt(2))/2 and I know that to be the correct answer for where the maximum E occurs; but upon attempting to plug this back into the original equation to find what the maximum E would be, I get the wrong answer every time. Any advice as to what I'm doing wrong? Any help would be greatly appreciated.