CAIE Further Paper 1 2024 June — Question 3 14 marks

Exam BoardCAIE
ModuleFurther Paper 1 (Further Paper 1)
Year2024
SessionJune
Marks14
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicLinear transformations
TypeDecompose matrix into transformation sequence
DifficultyStandard +0.3 This is a straightforward Further Maths question testing standard matrix transformation concepts: decomposing a product into component transformations (shear and stretch, both routine to identify), finding invariant lines (standard eigenvalue-related technique), and using determinant for area scaling. All parts follow textbook procedures 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 products4.03g Invariant points and lines4.03i Determinant: area scale factor and orientation

3 The matrix \(\mathbf { M }\) is given by \(\mathbf { M } = \left( \begin{array} { l l } 1 & 2 \\ 0 & 1 \end{array} \right) \left( \begin{array} { l l } 7 & 0 \\ 0 & 1 \end{array} \right)\).
  1. The matrix \(\mathbf { M }\) represents a sequence of two geometrical transformations in the \(x - y\) plane. Give full details of each transformation, and make clear the order in which they are applied. [4]
  2. Find the equations of the invariant lines, through the origin, of the transformation represented by \(\mathbf { M }\).
    The triangle \(D E F\) in the \(x - y\) plane is transformed by \(\mathbf { M }\) onto triangle \(P Q R\) .
  3. Given that the area of triangle \(P Q R\) is \(35 \mathrm {~cm} ^ { 2 }\) ,find the area of triangle \(D E F\) .

Question 3(a):
AnswerMarks Guidance
AnswerMarks Guidance
[One-way] stretch, shearB1 Both types.
Stretch followed by shearB1 Correct order.
Stretch parallel to the \(x\)-axis, scale factor 7B1
Shear, \(x\)-axis fixed, with \((0,1)\) mapped to \((2,1)\)B1
Question 3(b):
AnswerMarks Guidance
AnswerMarks Guidance
\(\mathbf{M} = \begin{pmatrix} 7 & 2 \\ 0 & 1 \end{pmatrix}\)B1
\(\begin{pmatrix} 7 & 2 \\ 0 & 1 \end{pmatrix}\begin{pmatrix} x \\ y \end{pmatrix} = \begin{pmatrix} 7x+2y \\ y \end{pmatrix}\)B1 FT Transforms \(\begin{pmatrix} x \\ y \end{pmatrix}\) to \(\begin{pmatrix} X \\ Y \end{pmatrix}\).
\(mx = m(7x + 2mx)\)M1 Uses \(y = mx\) and \(Y = mX\).
\(2m^2 + 6m = 0\)A1
\(y = 0\) and \(y = -3x\)A1 SCB1 if M0 and both straight lines correct
Question 3(c):
AnswerMarks Guidance
AnswerMarks Guidance
Area of \(PQR =7 \times\) Area of \(DEF\)
Area of \(DEF = 5 \text{ cm}^2\)A1 SCB1 for an answer of 245 (\(35 \times 7\))
## Question 3(a):

| Answer | Marks | Guidance |
|--------|-------|----------|
| [One-way] stretch, shear | **B1** | Both types. |
| Stretch followed by shear | **B1** | Correct order. |
| Stretch parallel to the $x$-axis, scale factor 7 | **B1** | |
| Shear, $x$-axis fixed, with $(0,1)$ mapped to $(2,1)$ | **B1** | |

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## Question 3(b):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $\mathbf{M} = \begin{pmatrix} 7 & 2 \\ 0 & 1 \end{pmatrix}$ | **B1** | |
| $\begin{pmatrix} 7 & 2 \\ 0 & 1 \end{pmatrix}\begin{pmatrix} x \\ y \end{pmatrix} = \begin{pmatrix} 7x+2y \\ y \end{pmatrix}$ | **B1 FT** | Transforms $\begin{pmatrix} x \\ y \end{pmatrix}$ to $\begin{pmatrix} X \\ Y \end{pmatrix}$. |
| $mx = m(7x + 2mx)$ | **M1** | Uses $y = mx$ and $Y = mX$. |
| $2m^2 + 6m = 0$ | **A1** | |
| $y = 0$ and $y = -3x$ | **A1** | SCB1 if M0 and both straight lines correct |

---

## Question 3(c):

| Answer | Marks | Guidance |
|--------|-------|----------|
| Area of $PQR = |7| \times$ Area of $DEF$ | **M1** | |
| Area of $DEF = 5 \text{ cm}^2$ | **A1** | SCB1 for an answer of 245 ($35 \times 7$) |

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3 The matrix $\mathbf { M }$ is given by $\mathbf { M } = \left( \begin{array} { l l } 1 & 2 \\ 0 & 1 \end{array} \right) \left( \begin{array} { l l } 7 & 0 \\ 0 & 1 \end{array} \right)$.
\begin{enumerate}[label=(\alph*)]
\item The matrix $\mathbf { M }$ represents a sequence of two geometrical transformations in the $x - y$ plane.

Give full details of each transformation, and make clear the order in which they are applied. [4]
\item Find the equations of the invariant lines, through the origin, of the transformation represented by $\mathbf { M }$.\\

The triangle $D E F$ in the $x - y$ plane is transformed by $\mathbf { M }$ onto triangle $P Q R$ .
\item Given that the area of triangle $P Q R$ is $35 \mathrm {~cm} ^ { 2 }$ ,find the area of triangle $D E F$ .
\end{enumerate}

\hfill \mbox{\textit{CAIE Further Paper 1 2024 Q3 [14]}}