Hey everyone. The last few days I work on a non-linear PDE. 

U*`∂`(F(s))/`∂`(x) = -k*sigma*cos(theta)*`∂`(F(s)*kro(s)*`∂`(J(s))/`∂`(x))/(`μo`*sqrt(k/phi)*`∂`(x));

with boundary conditions: when x=-∞: s=swi       and  

x=L : U*dF(s)+k*sigma*F(s)*kro(s)*`∂`(J(s))/(`μo`*sqrt(k/phi)*`∂`(x))

I need to plot...