ABSTRACT
Owing to the complexity of the PDEs involved in some mathematical mod els, it is not always possible to find an exact solution to an initial/boundary value problem. The next best thing in such situations is to compute an ap proximate solution instead. This is the idea behind the method of asymp totic expansion, which is applicable to problems th a t depend on a small positive param eter and relies on the expansion of the solution in a series of powers of the parameter. If the series converges, then the technique is called a perturbation method; when the series diverges but is asymptotic (in a sense th a t will be explained below), we have an asymptotic method.
