Easy -1.8 This is a straightforward recall question requiring only the definition of a singular matrix (determinant = 0) and calculation of 2×2 determinants. The second matrix has clearly proportional rows (2nd row = 2×1st row), making it immediately identifiable as singular without calculation. This is below typical A-level difficulty as it's pure recognition with no problem-solving element.
1 Which of the following matrices is singular?
Circle your answer.
\(\left[ \begin{array} { l l } 1 & 0 \\ 0 & 1 \end{array} \right]\)
\(\left[ \begin{array} { l l } 1 & 1 \\ 2 & 2 \end{array} \right]\)
\(\left[ \begin{array} { l l } 0 & 1 \\ 1 & 0 \end{array} \right]\)
\(\left[ \begin{array} { c c } 1 & - 2 \\ 1 & 2 \end{array} \right]\)
1 Which of the following matrices is singular?\\
Circle your answer.\\
$\left[ \begin{array} { l l } 1 & 0 \\ 0 & 1 \end{array} \right]$\\
$\left[ \begin{array} { l l } 1 & 1 \\ 2 & 2 \end{array} \right]$\\
$\left[ \begin{array} { l l } 0 & 1 \\ 1 & 0 \end{array} \right]$\\
$\left[ \begin{array} { c c } 1 & - 2 \\ 1 & 2 \end{array} \right]$
\hfill \mbox{\textit{AQA Further Paper 2 2021 Q1 [1]}}