I attached my program. It is a problem of solving 6 third-order ODEs with 18 boundary conditions. After using NDSolve to get the numerical solutions of the problem, I plotted the first and second derivatives. I believe that the graphs of the first and second derivatives are wrong, since they are totally different from what I expected. Besides, in the boundary conditions, there is one stipulating that u2a''[1/2]==0. But after I extracted the results, I got u2a''[1/2]==-0.614559. So there is definitely something wrong, either with my code or with the algorithm of NDSolve. I don't know where the problem is. Could anyone help me? Many thanks!!
Attachments: