1. The problem statement, all variables and given/known data Two points charges. q1=2.4e-6 C is located at (0,0) q2=-5.7e-6 C is located at (3,0) I must calculate the magnitude of the Electric field at (0,0) 2. Relevant equations E=kq/r^2 ; k=9e9 3. The attempt at a solution The electric field at (0,0) due to q2=9e9x(-5.7e-6)/3^2 = -5700N/C Next would be to add the electric field at (0,0) due to q1. However, I don't know how to calculate the field as distance is r=0 which doesn't work with the formula. How do I calculate the electric field due to a point charge AT the point charge?