# How to get rid of these matrices?

I have divided a complicated Lagrangian to some separated terms to be able to Simplify it. The thing is, in the general case (non-divided Lagrangian) the problem is too complicated to solve, and in the other case, there are some strange matrices. How can I convert them to a computable form?

I have heard something about BasisExpand and FromBasisExpand, are there useful?

• Put ClearAll["Global*"]` before your code? – kglr Aug 25 '19 at 14:11