Lecture 19: Turning points and Airy functions

The WKB method helps us study a class of second-order ODES known as Schrödinger equations. These are closely related to the famous Schrödinger equation of quantum mechanics. In this lecture, Prof. Strogatz shows how to use the WKB method to approximate the solutions of Schrödinger equations in problems that have "turning points". At such points, the solutions change from decaying exponentially to oscillating.The matching between the two types of behavior involves special functions known as Airy functions.