If $A$ and $B$ are two square matrices of same order such that $AB = A$ and $BA = B$, then the value of $A^{2024} + B^{2024}$ is equal to |
$2024A + 2024B$ $O$ $A + B$ $A - B$ |
$A + B$ |
The correct answer is Option (3) → $A + B$ Given: AB = A and BA = B From AB = A ⇒ A(B − I) = 0 From BA = B ⇒ (A − I)B = 0 Multiply AB = A on left by A: A²B = A² ⇒ using AB = A ⇒ A² = A Similarly, multiply BA = B on left by B: B²A = B² ⇒ using BA = B ⇒ B² = B Hence, both A and B are idempotent matrices: $A^n = A$ and $B^n = B$ for all $n \ge 1$ Therefore, $A^{2024} + B^{2024} = A + B$ $A^{2024} + B^{2024} = A + B$ |