I have a problem with the DSolve command. Using it on a 4th order differential equation yields a complex solution. But I know that the solution is a real function.
In the attached notebook the complex solution with DSolve has the name
Subscript[\[Sigma], peel, GR, selbst][x]
The solution derived manually is real and has the name
Subscript[\[Sigma], peel, GR][x]
It must be possible to convert the symbolic complex solution to the symbolic real one but I really don't now how.
I would be happy for every advice.
Attachment: DGL_4th_Order_with_own_solution.nb, URL: ,