Exercise 5

Singular or nonsingular? Use the determinant to decide.

• (a)  $\begin{pmatrix}2&1&1\\ 3&2&2\\ 0&1&4\end{pmatrix}$     (b)  $\begin{pmatrix}1&0&1\\ 2&1&1\\ 4&1&3\end{pmatrix}$     (c)  $\begin{pmatrix}2&1&0\\ 3&-2&0\\ 1&0&0\end{pmatrix}$