(a) Show that the potential due to a double-layer surface S with a dipole density (r S ) n is where d is the

(a) Show that the potential due to a double-layer surface S with a dipole density τ (r_S ) ˆn is where dΩ is the differential element of solid angle as viewed from r.(b) Use this result to derive the matching condition at a double-layer surface.

(r) = 1 d(rs),