Exercise 2

Which of these matrices could be used to change bases?

• (a)  $\begin{pmatrix}1&2\\ 3&4\end{pmatrix}$     (b)  $\begin{pmatrix}0&-1\\ 1&-1\end{pmatrix}$     (c)  $\begin{pmatrix}2&3&-1\\ 0&1&0\end{pmatrix}$     (d)  $\begin{pmatrix}2&3&-1\\ 0&1&0\\ 4&7&-2\end{pmatrix}$     (e)  $\begin{pmatrix}0&2&0\\ 0&0&6\\ 1&0&0\end{pmatrix}$