Demonstrate that the potential of the field generated by a dipole with the electric moment p (Fig. 3.4) may be represented as = pr/40r3, where

Demonstrate that the potential of the field generated by a dipole with the electric moment p (Fig. 3.4) may be represented as φ = pr/4πε0r3, where r is the radius vector.
Using this expression, find the magnitude of the electric field strength vector as a function of r