OCR FP1 — Question 2 6 marks

Exam BoardOCR
ModuleFP1 (Further Pure Mathematics 1)
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicMatrices
TypeMatrix powers and patterns
DifficultyStandard +0.3 This is a straightforward FP1 matrix question requiring matrix multiplication and algebraic manipulation. Part (i) is routine computation, and part (ii) uses a standard technique (multiplying the given relation by A^{-1}) that students are explicitly taught. While it's Further Maths content, it requires no novel insight and follows a predictable pattern, making it slightly easier than average overall.
Spec4.03b Matrix operations: addition, multiplication, scalar4.03o Inverse 3x3 matrix

The matrices \(\mathbf{A}\) and \(\mathbf{I}\) are given by \(\mathbf{A} = \begin{pmatrix} 1 & 2 \\ 1 & 3 \end{pmatrix}\) and \(\mathbf{I} = \begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix}\) respectively.
  1. Find \(\mathbf{A}^2\) and verify that \(\mathbf{A}^2 = 4\mathbf{A} - \mathbf{I}\). [4]
  2. Hence, or otherwise, show that \(\mathbf{A}^{-1} = 4\mathbf{I} - \mathbf{A}\). [2]

The matrices $\mathbf{A}$ and $\mathbf{I}$ are given by $\mathbf{A} = \begin{pmatrix} 1 & 2 \\ 1 & 3 \end{pmatrix}$ and $\mathbf{I} = \begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix}$ respectively.

\begin{enumerate}[label=(\roman*)]
\item Find $\mathbf{A}^2$ and verify that $\mathbf{A}^2 = 4\mathbf{A} - \mathbf{I}$. [4]
\item Hence, or otherwise, show that $\mathbf{A}^{-1} = 4\mathbf{I} - \mathbf{A}$. [2]
\end{enumerate}

\hfill \mbox{\textit{OCR FP1  Q2 [6]}}