If A and B are two matrices of order 2 × 2 such that A is a symmetric matrix and B is a skew-symmetric matrix, then: |
$A^2$ is also a symmetric matrix $B^2$ is also a skew-symmetric matrix $A+B$ is an identity matrix $A-B$ is a null matrix |
$A^2$ is also a symmetric matrix |
The correct answer is Option (1) → $A^2$ is also a symmetric matrix For any symmetric matrix $A$, $A^T=A$. $(A^2)^T=(AA)^T=A^TA^T=AA=A^2$, so $A^2$ is symmetric ✅ For any skew-symmetric matrix $B$, $B^T=-B$. $(B^2)^T=(BB)^T=B^TB^T=(-B)(-B)=BB=B^2$, so $B^2$ is symmetric, not skew-symmetric ❌ $A+B$ cannot be an identity matrix in general ❌ $A-B$ cannot be a null matrix in general ❌ Correct answer: $A^2$ is also a symmetric matrix. |