function rhs = wave1_f(x,u)
% odefile for wave equation code (to be called by ode45)
% 
% 2004-03-01 kfp

global w a;

tau = (3+tanh(a*x)).^2;
lambda = 4;

rhs = [u(2)./tau;  -lambda*w^2*u(1)];

