ABSTRACT
The eigenfunction expansion technique is designed for initial boundary value problems (IBVPs) with a nonhomogeneous equation and homogeneous boundary conditions (BCs). This chapter consider problems with several types of BCs and presents an example of derivation of eigenvalues and eigenfunctions associated with the IBVP. The method of eigenfunction expansion works equally well for IBVPs with mixed BCs. The method of eigenfunction expansion can be extended to some IBVPs or BVPs for more general partial differential equations.
