ABSTRACT
In the previous chapters, we sought solutions to the heat and wave equations via Green’s functions. In this chapter, we turn to the reduced wave equation
∇2u+ λu = −f(r). (6.0.1) Equation 6.0.1, generally known as Helmholtz’s equation, includes the special case of Poisson’s equation when λ = 0. Poisson’s equation has a special place in the theory of Green’s functions because George Green invented his technique for its solution.
