1. The problem statement, all variables and given/known data 1) (AB)^-1=A^-1B^-1 A and B are nonsingular nxn 2) If A is nonsingular then A^-1 is nonsingular also and then (A^-1)^-1=A 3. The attempt at a solution 1) I do know that I have to multiply but I don´t know why. Can you tell me why?? This is how I do it: ((AB)^-1)*(A^-1B^-1 ))A(BB^-1)A^-1=A*In*A^-1=A*A^-1=In 2) ((A^-1)^-1)*A = ?????