Solved Examples on Matrices

Illustration 3: If A and B are square matrices of equal degree, then which of the following is correct? (1995)

1. A+B = B+A                                                   2. A+B = A-B

3. A-B = B-A                                                     4. AB = BA

Solution:Since A and B are square matrices and are also of equal degree so the addition must be commutative.

Hence, we must have A+B = B+A.