I have been presented with a problem, as described above, with a difficult right hand side of e^{x}cosx; an example would be y'' + 2y' +y = (e^{x}cosx). I have utilized the auxiliary equation to find the complementary solution, but which form do I need to use to find my particular integral? I have begun to use Ae^{x(}cosx) + Be^{x(}sinx), but I'm fairly certain that isn't right. Any help would be fantastic!