Originally Posted by
mr fantastic Correct. The example given does not answer the question. Also, since one of them is the identity matrix they obviously commute .....
Surely it's not hard too find two matrices that satisfy the requirements of (b). In fact, I bet you could choose to 2x2 matrices at random that would work. Then the answer to c is obvious.
As for (a), two trivial matrices that satisfy the requirements are
[1, 1]
[1, 1]
[2, 2]
[2, 2]
It is not too hard to construct less trivial examples .....