If A and B are 2 × 2 matrices, then which of the following is true ?
A. (A + B)2 = A2 + B2 + 2AB
B. (A - B)2 = A2 + B2 - 2AB
C. (A - B)(A + B) = A2 + AB- BA - B2
D. (A - B)(A + B) = A2 - B2
Answer:A
If A and B are 2 × 2 matrices, then which of the following is true ?
A. (A + B)2 = A2 + B2 + 2AB B. (A - B)2 = A2 + B2 - 2AB C. (A - B)(A + B) = A2 + AB- BA - B2 D. (A - B)(A + B) = A2 - B2