On the construction of boundary conditons for a nonlinear operator

[Calin Gheorghiu]

Dear All,

I try:

N = chebop(@(x,u) (2*x*diff(u,2)+diff(u))*(u+1)+20*x*(u+1),[0, 1])

N.lbc=@(x,u)(x^(1/2))*diff(u) % Boundary conditions

% N.lbc=@(x,u)(sqrt(x))*diff(u)

N.rbc='neumann'

and I get the error:

Error using chebop/parseBC
Number of inputs to BCs do not match operator.

Error in chebop/set.lbc (line 473)
            N.lbc = parseBC(N, val, 'lrbc');

Error in Michaelis_Menten (line 12)
N.lbc=@(x,u)(x^(1/2))*diff(u)         % Boundary conditions

Does anyone have an idea where the mistake could be?

Regards and thanks,

Calin