Edexcel F1 2018 January — Question 7 11 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2018
SessionJanuary
Marks11
PaperDownload PDF ↗
TopicMatrices
TypeMatrix satisfying given equation
DifficultyStandard +0.3 This is a straightforward Further Maths question testing standard matrix operations. Part (i) involves routine inverse and squaring of 2×2 matrices, then solving a simple equation for k. Part (ii) requires decomposing a transformation matrix into stretch and rotation components using standard formulas. All techniques are direct applications of F1 syllabus content with no novel problem-solving required, making it slightly easier than average even for Further Maths.
Spec4.03d Linear transformations 2D: reflection, rotation, enlargement, shear4.03e Successive transformations: matrix products4.03n Inverse 2x2 matrix4.03o Inverse 3x3 matrix

7. (i) $$\mathbf { A } = \left( \begin{array} { r r } 6 & k \\ - 3 & - 4 \end{array} \right) , \text { where } k \text { is a real constant, } k \neq 8$$ Find, in terms of \(k\),
  1. \(\mathbf { A } ^ { - 1 }\)
  2. \(\mathbf { A } ^ { 2 }\) Given that \(\mathbf { A } ^ { 2 } + 3 \mathbf { A } ^ { - 1 } = \left( \begin{array} { r r } 5 & 9 \\ - 3 & - 5 \end{array} \right)\)
  3. find the value of \(k\).
    (ii) $$\mathbf { M } = \left( \begin{array} { c c } - \frac { 1 } { 2 } & - \sqrt { 3 } \\ \frac { \sqrt { 3 } } { 2 } & - 1 \end{array} \right)$$ The matrix \(\mathbf { M }\) represents a one way stretch, parallel to the \(y\)-axis, scale factor \(p\), where \(p > 0\), followed by a rotation anticlockwise through an angle \(\theta\) about \(( 0,0 )\).
    1. Find the value of \(p\).
    2. Find the value of \(\theta\).

7. (i)

$$\mathbf { A } = \left( \begin{array} { r r } 
6 & k \\
- 3 & - 4
\end{array} \right) , \text { where } k \text { is a real constant, } k \neq 8$$

Find, in terms of $k$,
\begin{enumerate}[label=(\alph*)]
\item $\mathbf { A } ^ { - 1 }$
\item $\mathbf { A } ^ { 2 }$

Given that $\mathbf { A } ^ { 2 } + 3 \mathbf { A } ^ { - 1 } = \left( \begin{array} { r r } 5 & 9 \\ - 3 & - 5 \end{array} \right)$
\item find the value of $k$.\\
(ii)

$$\mathbf { M } = \left( \begin{array} { c c } 
- \frac { 1 } { 2 } & - \sqrt { 3 } \\
\frac { \sqrt { 3 } } { 2 } & - 1
\end{array} \right)$$

The matrix $\mathbf { M }$ represents a one way stretch, parallel to the $y$-axis, scale factor $p$, where $p > 0$, followed by a rotation anticlockwise through an angle $\theta$ about $( 0,0 )$.\\
(a) Find the value of $p$.\\
(b) Find the value of $\theta$.

\begin{center}

\end{center}
\end{enumerate}

\hfill \mbox{\textit{Edexcel F1 2018 Q7 [11]}}