Why is that electric field intensity at a point on the equatorial line due to an electric dipole taken as negative?

The direction of electric field at a point on the equatorial line due to an electric dipole is

The electric potential at a point on the equatorial line of a electric dipole is

The direction of electric field intensity at a point on the equatorial line of an electric dipole of dipole moment is

Derive the expression for electric field intensity at a point on equatorial line of a dipole

The electric field due to dipole at a point on the equatorial line given by

Obtain an expression for the electric field intenstiy at a point on the equatorial line of an electric dipole.

Derive an expression for electric field intensity at a point on the axial line of an electric dipole.