Sorry for this second question!
How do I prove that A^2 = A in Matrices given that AB=A and BA=A.
I tried to expand the LHS and then intend to get at AB so as to end up with RHS=A in the end but I'm stuckm
A^2 = A
AA = A
A(AB) = A
If I keep expandin, I'll keep getting more Bs and As..
Please help me.