Q1: Which of the following matrices is not a diagonal matrix?

A1: $$ \begin{pmatrix} 2 & 1 & 0 \ 0 & 0 & 0 \end{pmatrix} $$

A2: $$ \begin{pmatrix} 2 & 0 & 0 \ 0 & 1 & 0 \end{pmatrix} $$

A3: $$ \begin{pmatrix} 2 & 0 \ 0 & 1 \ 0 & 0 \end{pmatrix} $$

A4: $$ \begin{pmatrix} 2 & 0 & 0 \ 0 & 3 & 0 \ 0 & 0 & 1 \end{pmatrix} $$

A5: $$ \begin{pmatrix} 2 & 0 & 0 \ 0 & 0 & 0 \ 0 & 0 & 1 \end{pmatrix} $$

Q2: Which of the following matrices is not an upper triagonal matrix?

A1: $$ \begin{pmatrix} 2 & 1 & 0 \ 1 & 0 & 0 \end{pmatrix} $$

A2: $$ \begin{pmatrix} 2 & 1 \ 0 & 1 \end{pmatrix} $$

A3: $$ \begin{pmatrix} 2 & 0 \ 0 & 1 \end{pmatrix} $$

A4: $$ \begin{pmatrix} 2 & 0 & 0 \ 0 & 3 & 0 \ 0 & 0 & 1 \end{pmatrix} $$

A5: $$ \begin{pmatrix} 2 & 5 & 5 \ 0 & 4 & 7 \ 0 & 0 & 1 \end{pmatrix} $$

Q3: Which of the following matrices is not a symmetric matrix?

A1: $$ \begin{pmatrix} 2 & 1\ 0 & 1 \end{pmatrix} $$

A2: $$ \begin{pmatrix} 2 & 0 \ 0 & 1 \end{pmatrix} $$

A3: $$ \begin{pmatrix} 2 & 0 \ 0 & 2 \end{pmatrix} $$

A4: $$ \begin{pmatrix} 2 & 0 & 0 \ 0 & 3 & 0 \ 0 & 0 & 1 \end{pmatrix} $$

A5: $$ \begin{pmatrix} 2 & 0 & -1 \ 0 & 0 & 0 \ -1 & 0 & 1 \end{pmatrix} $$