Electric Field

A thin nonconducting rod of finite length $L$ has a chrage $q$ spread uniformly along it. Show that the magnitude $E$ of the electric field at point $P$ on the perpendicular bisector of the rod is given by $E = \frac{q}{2\pi\epsilon_{0}y}\frac{1}{(L^2 + 4y^2)^{1/2}}$.