Let the scalar function ƒ be the solution of the Laplace's equation ∇f = δ(r - r') where r'=-2i+3j is a position vector on the x y plane, where r denotes the position vector, r' =-2i +3j , and δ(r) denotes the delta function. Give the formula for the solution of Laplace's equation in Cartesian coordinates indicating where the solution is defined.