Let A be any square matrix of order 3 and $B =\begin{bmatrix}0&-4&2\\4&0&3\\-2&-3&0\end{bmatrix}$. Then the matrix $ABA^T$ is a |
Symmetric matrix Skew symmetric matrix Null matrix Diagonal matrix |
Skew symmetric matrix |
The correct answer is Option (2) → Skew symmetric matrix $B=\begin{pmatrix}0&-4&2\\4&0&3\\-2&-3&0\end{pmatrix}$ $B$ satisfies $B^{T}=-B$, therefore $B$ is a skew–symmetric matrix. Consider the matrix $ABA^{T}$. $(ABA^{T})^{T}=A\,B^{T}\,A^{T}=A(-B)A^{T}=-(ABA^{T})$ This shows that $ABA^{T}$ is also skew–symmetric. The matrix $ABA^{T}$ is a skew–symmetric matrix. |