Is it always true that AB = BA?

A good answer might be:

NO! Even when both products can be formed they are rarely equal.

Not Commutative

For example, calculate both of the following products (you might wish to use paper and pencil):

ProblemThink FirstResult

The results show that in general for matrices A and B, AB =/= BA.


Is A4×4 04×4== 04×4 A4×4,   where 0 is the zero matrtix?