I’m working on deriving the equation of motion (16) from equation (9) (see attached image), but I’ve encountered a couple of issues in Maple. i) The variational derivative of Lagrangian, and ii) the commutator is zero, which isn’t expected.

How do we fix these issues? Are there any specific packages regarding the construction of Lagrangian?

VariationDerivative.mw

Can we find the conditions on A1, A2, B1, B2, beta1, and beta2 for which numerator of Eq. (1) is zero? ss.mw

How do I solve equation (1) for omega, rho, lambda1, and lambda2? verif.mw

can we express 'X' in terms of 'L'? i.e., X = (some const)*L XintoL.mw

Why does 'simplify' not work when calculating Eigenvectors? Further, how can we express (2) in a more simplified form by using 'simplify'?simplify.mw