You're on the right track. Since we know that for all nonsingular matrices , that
So for three nonsingular matrices
Prove that for three non-singular matrices A, B, C that
I know that for two square matrices, C, D, say, . I tried using this result to prove , by considering AB as one square matrix, and multiplying by C, and here is my problem.
, I don't know how to continue after this. Or am I off the right track?