A formal uniform asymptotic solution of the differential equation large, when D contains any number and order of poles and turning points, is constructed. The development is a generalization of Langer’s method. An asymptotic relation, between the Wronskian of any pair of linearly independent solutions of the differential equation and the Wronskian of the pair of corresponding solutions of the comparison equation, is derived. A formal uniform asymptotic solution of a system of two first-order ordinary differential equation is also obtained.
Journal of Mathematical Analysis and Applications 09/1988; 134(2-134):329-354. DOI:10.1016/0022-247X(88)90027-3