pdepe coupled boundary conditions

I'm solving a set of two PDEs with boundary conditions (du1/dx, du2/dx) = 0 for x=0 and x=1. My function f from pdefun is f = [k1*du/dx(1) - k2*u(1)*du/dx(2); k3*du/dx(2)]. I cannot find q(x,t) and p(x,t,u) to write my boundary conditions in the form pdepe expects. How do I find q and p when dealing with coupled systems like this one? Is it even necessarily possible? Thanks.

Answer 1

[Torsten]

pl = pr = 0, ql = qr = 1 for both components u1 and u2. What's the problem ?