Engineering Physics

A particle of charge −q and a mass m is placed midway between two equal positive charges $q_{0}$ of separation d. If the negative charge −q is displaced in perpendicular direction to the line joining them and released, show that the particle describes a SHM with a period

$$T = {[\frac{{\varepsilon}_{0}m{\pi}^{3}{d}^{3}}{q{q}_{0}}]}^{1/2}$$