A two-dimensional disk of radius R carries a uniform charge per unit area > 0. (a) Calculate

A two-dimensional disk of radius R carries a uniform charge per unit areaσ > 0.
(a) Calculate the potential at any point on the symmetry axis of the disk.
(b) Calculate the potential at any point on the rim of the disk.
(c) Sketch the electric field pattern everywhere in the plane of the disk.
(d) Calculate the electrostatic total energy U_E of the disk.