@Preben Alsholm , I'm sorry by my mistake.

To solve this problem on hand, I need to assume f1(y) like a linear function, so:

f1(y) = C1*y+C2

With this simplification, the system is solvable. I don't know if this levy can be done in Maple.

@Carl Love, I'm sorry by you too.

With sincere thanks,

Arthur

@Carl Love , How could I solve this system so?

Without Maple(on pencil and paper) I need of the third equation to solve.

I will try to show you why:

From Frist equation: diff(u(x, y), x) = -(2/3)*(3*h^3*nu+9*h^2*nu*y-12*nu*y^3+36*x^2*y+56*y^3)/h^3

So: u(x,y) = integrate(-(2/3)*(3*h^3*....+56*y^3)/h^3) + F(y);

The same for second equation is: v(x,y) = integrate((2/3)*(36*nu*...*y-12*y^3)/h^3 + G(x).

diff(x(x,y),y)+diff(v(x,y),x) = diff(integrate(-(2/3)*(3*h^3*....+56*y^3)/h^3),y) + F'(y) + diff(integrate((2/3)*(36*nu*...*y-12*y^3)/h^3),y) + F'(x) = [Third equation] = -(6*(1+nu))*x*(h^2-4*y^2)/h^3

Now, applying the initial conditions I can solve the system and find u(x,y) and v(x,y). But I don't know how to put it on Maple.

Thanks for your reply.

I'm so sorry by my bad english again.