Question

$A=\left[\begin{array}{ccc}1& 0& 0\\ 0& -5& 0\\ 0& 0& 9\end{array}\right]$ is a ________.

• A. unit matrix
• B. rectangular matrix
• C. diagonal matrix
• D. scalar matrix

Answer 1

The correct option is C

diagonal matrix

A diagonal matrix is a matrix in which all the elements other than the diagonal are zero. Hence this is a diagonal matrix.