> restart;

> A:=Matrix([[a,b],[c,d]]);

> B:=Matrix([[p,q],[r,s]]);

> A^2;

> A^3;

> A.B;

> B.A;

> A+B;

> A.B-B.A;

> with(linalg);

Warning, the protected names norm and trace have been redefined and unprotected

> trace(A.B);

> trace(B.A);

>