Question
A charge is fixed at each of the points x=x0, x=3x0, x=5x0…… infinite, on the x-axis and a charge -q is fixed at each of the points x=2x0, x=4x0, x=6x0,…… infinite. Here x0 is a positive constant. Take the electric potential at a point due to a charge Q at a distance r from it to be Q(4πϵ0r). Then, the potential at the origin due to the above system of charges is