OCR FP1 2012 January — Question 5 6 marks

Exam BoardOCR
ModuleFP1 (Further Pure Mathematics 1)
Year2012
SessionJanuary
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicLinear transformations
TypeWrite down transformation matrix
DifficultyModerate -0.8 This is a straightforward Further Maths question testing basic knowledge of transformation matrices. Part (a) requires recall of a standard reflection matrix, part (b)(i) asks students to identify a simple stretch from a diagonal matrix, and part (b)(ii) connects the determinant to area scale factor—all routine applications with no problem-solving or novel insight required.
Spec4.03d Linear transformations 2D: reflection, rotation, enlargement, shear4.03h Determinant 2x2: calculation

5
  1. Find the matrix that represents a reflection in the line \(y = - x\).
  2. The matrix \(\mathbf { C }\) is given by \(\mathbf { C } = \left( \begin{array} { l l } 1 & 0 \\ 0 & 4 \end{array} \right)\).
    1. Describe fully the geometrical transformation represented by \(\mathbf { C }\).
    2. State the value of the determinant of \(\mathbf { C }\) and describe briefly how this value relates to the transformation represented by \(\mathbf { C }\).

Question 5(a):
AnswerMarks Guidance
AnswerMarks Guidance
\(\begin{pmatrix}0&-1\\-1&0\end{pmatrix}\)B1, B1 Each column correct
[2]
Question 5(b)(i):
AnswerMarks Guidance
AnswerMarks Guidance
Stretch, scale factor 4 in the \(y\) directionB1, DB1 Not "in the \(y\)-axis"
[2]
Question 5(b)(ii):
AnswerMarks Guidance
AnswerMarks Guidance
\(4\)B1, B1 Correct value of determinant; Scale factor for area (allow scale factor of stretch or equiv.)
[2]
## Question 5(a):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $\begin{pmatrix}0&-1\\-1&0\end{pmatrix}$ | B1, B1 | Each column correct |
| **[2]** | | |

---

## Question 5(b)(i):

| Answer | Marks | Guidance |
|--------|-------|----------|
| Stretch, scale factor 4 in the $y$ direction | B1, DB1 | Not "in the $y$-axis" |
| **[2]** | | |

---

## Question 5(b)(ii):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $4$ | B1, B1 | Correct value of determinant; Scale factor for area (allow scale factor of stretch or equiv.) |
| **[2]** | | |

---
5
\begin{enumerate}[label=(\alph*)]
\item Find the matrix that represents a reflection in the line $y = - x$.
\item The matrix $\mathbf { C }$ is given by $\mathbf { C } = \left( \begin{array} { l l } 1 & 0 \\ 0 & 4 \end{array} \right)$.
\begin{enumerate}[label=(\roman*)]
\item Describe fully the geometrical transformation represented by $\mathbf { C }$.
\item State the value of the determinant of $\mathbf { C }$ and describe briefly how this value relates to the transformation represented by $\mathbf { C }$.
\end{enumerate}\end{enumerate}

\hfill \mbox{\textit{OCR FP1 2012 Q5 [6]}}