Let A = \begin{pmatrix} 1 & 0 & 3 \\ 2 & 1 & -1 \\ 1 & -1 & 1 \end{pmatrix}.
Show that \mathbf{AB} = -9\mathbf{I}.
The mark scheme is shown once you've answered.
Practise this question\mathbf{B}, where \mathbf{B} = \mathbf{A}^2 - 3\mathbf{A} - \mathbf{I}.[3 marks]\mathbf{A}^{-1}, of \mathbf{A}.[2 marks]\mathbf{B} \begin{pmatrix} x \\ y \\ z \end{pmatrix} = \begin{pmatrix} 3 \\ -1 \\ 2 \end{pmatrix}.[3 marks]More practice: the rest of this paper · more Matrices and Systems of Linear Equations questions · all CAPE Pure Mathematics Unit 2 past papers