An integrating factor to find the canonical variables of a class of wave equations

A method to facilitate the determination of canonical variables of the one-dimensional wave equation in nonhomogeneous media is presented. In order to solve the second-order hyperbolic partial differential equation a transformation from the independent real variables x and y to two canonical variables is used. A method is presented which shows a way of determining a solution when the wave-speed function /spl sigma/(x,y) meets certain requirements on continuity, and the function u(x,y) meets certain integrability requirements. The method depends on finding an integrating factor, f(x,y).<>