4 The matrices \(\mathbf { A }\) and \(\mathbf { B }\) are such that
$$\mathbf { A } = \left[ \begin{array} { c c c }
2 & a & 3 \\
0 & - 2 & 1
\end{array} \right] \quad \text { and } \quad \mathbf { B } = \left[ \begin{array} { c c }
1 & - 3 \\
- 2 & 4 a \\
0 & 5
\end{array} \right]$$
4
- Find the product \(\mathbf { A B }\) in terms of \(a\).
[0pt]
[2 marks]
4 - Find the determinant of \(\mathbf { A B }\) in terms of \(a\).
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□ \(\quad \mathbf { A } = \left[ \begin{array} { c c c } 2 & a & 3 \\ 0 & - 2 & 1 \end{array} \right]\) and \(\quad \mathbf { B } = \left[ \begin{array} { c c } 1 & - 3 \\ - 2 & 4 a \\ 0 & 5 \end{array} \right]\)
\(\mathbf { 4 }\) (a) Find the product \(\mathbf { A B }\) in terms of \(a\).
4 - Show that \(\mathbf { A B }\) is singular when \(a = - 1\)