Question

The matrix $\left[\begin{array}{ccc}1& 0& 0\\ 0& 2& 0\\ 0& 0& 0\end{array}\right]$ is a

• A. identity matrix
• B. symmetric matrix
• C. skew symmetric matrix
• D. none of these

Answer 1

Answer: (B)

Let $A=\left[\begin{array}{ccc}1& 0& 0\\ 0& 2& 0\\ 0& 0& 0\end{array}\right]\Rightarrow A^T=\left[\begin{array}{ccc}1& 0& 0\\ 0& 2& 0\\ 0& 0& 0\end{array}\right]=A$

$\therefore A$ is a symmetric matrix