function y = rhs(x,u,lambda)

%  initialize
y = zeros(size(u));

%  s-l functions
p = x;
q = 0;
r = x;

%  s-l ode:  u1 = u(x) & u2 = p(x) u'(x)
y(1) = u(2)/p;
y(2) = -(lambda*r - q)*u(1);