If A is a skew-symmetric matrix, then which of the following statements is NOT true? (A) A is singular if order of A is odd Choose the correct answer from the options given below. |
(A), (C) and (E) only (A) and (E) only (B), (D) and (E) only (B) and (D) only |
(B) and (D) only |
The correct answer is Option (4) → (B) and (D) only For a skew-symmetric matrix $A$, $A^T=-A$. (A) True: If order of $A$ is odd, then $\det(A)=\det(A^T)=\det(-A)=(-1)^n\det(A)=-\det(A)$ ⟹ $\det(A)=0$. So $A$ is singular. (B) False: A skew-symmetric matrix of odd order is singular, hence it cannot be non-singular. (C) True: For any skew-symmetric matrix, odd powers remain skew-symmetric, since $(A^{2k+1})^T=(-A)^{2k+1}=-A^{2k+1}$. (D) False: $A^{2025}$ is skew-symmetric, not symmetric. (E) True: All diagonal elements of a skew-symmetric matrix are zero. Statement (B) and Statement (D) is NOT true. |