CAIE P1 2022 March — Question 5 6 marks

Exam BoardCAIE
ModuleP1 (Pure Mathematics 1)
Year2022
SessionMarch
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicFunction Transformations
TypeSequence of transformations order
DifficultyModerate -0.8 Part (a) is routine completing the square with a coefficient factored out. Part (b) requires identifying transformations from completed square form, which is a standard textbook exercise testing recall of transformation rules. The circle/line problem appears unrelated to the transformation question. Overall, this is below average difficulty—straightforward application of well-practiced techniques with no problem-solving insight required.
Spec1.02e Complete the square: quadratic polynomials and turning points1.02w Graph transformations: simple transformations of f(x)1.03d Circles: equation (x-a)^2+(y-b)^2=r^2

5
  1. Express \(2 x ^ { 2 } - 8 x + 14\) in the form \(2 \left[ ( x - a ) ^ { 2 } + b \right]\).
    The functions \(f\) and \(g\) are defined by $$\begin{aligned} & \mathrm { f } ( x ) = x ^ { 2 } \quad \text { for } x \in \mathbb { R } \\ & \mathrm {~g} ( x ) = 2 x ^ { 2 } - 8 x + 14 \quad \text { for } x \in \mathbb { R } \end{aligned}$$
  2. Describe fully a sequence of transformations that maps the graph of \(y = \mathrm { f } ( x )\) onto the graph of \(y = \mathrm { g } ( x )\), making clear the order in which the transformations are applied. \includegraphics[max width=\textwidth, alt={}, center]{05e75fa2-81ae-44b1-b073-4100f5d911e0-08_679_1043_260_552} The circle with equation \(( x + 1 ) ^ { 2 } + ( y - 2 ) ^ { 2 } = 85\) and the straight line with equation \(y = 3 x - 20\) are shown in the diagram. The line intersects the circle at \(A\) and \(B\), and the centre of the circle is at \(C\).

Question 5(a):
AnswerMarks Guidance
AnswerMarks Guidance
\(2[\{(x-2)^2\}\ \{+3\}]\)B1 B1 B1 for \(a=2\), B1 for \(b=3\). \(2(x-2)^2+6\) gains B1B0
2
Question 5(b):
AnswerMarks Guidance
AnswerMarks Guidance
{Translation} \(\begin{pmatrix}\{2\}\\\{3\}\end{pmatrix}\) OR {Stretch} {\(y\) direction} {factor 2}B2,1,0 B2 for fully correct, B1 with two elements correct. \(\{\}\) indicates different elements
{Stretch} {\(y\) direction} {factor 2} OR {Translation} \(\begin{pmatrix}\{2\}\\\{6\}\end{pmatrix}\)B2,1,0 B2 for fully correct, B1 with two elements correct. \(\{\}\) indicates different elements
4
## Question 5(a):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $2[\{(x-2)^2\}\ \{+3\}]$ | B1 B1 | B1 for $a=2$, B1 for $b=3$. $2(x-2)^2+6$ gains B1B0 |
| | **2** | |

## Question 5(b):

| Answer | Marks | Guidance |
|--------|-------|----------|
| {Translation} $\begin{pmatrix}\{2\}\\\{3\}\end{pmatrix}$ OR {Stretch} {$y$ direction} {factor 2} | B2,1,0 | B2 for fully correct, B1 with two elements correct. $\{\}$ indicates different elements |
| {Stretch} {$y$ direction} {factor 2} OR {Translation} $\begin{pmatrix}\{2\}\\\{6\}\end{pmatrix}$ | B2,1,0 | B2 for fully correct, B1 with two elements correct. $\{\}$ indicates different elements |
| | **4** | |
5
\begin{enumerate}[label=(\alph*)]
\item Express $2 x ^ { 2 } - 8 x + 14$ in the form $2 \left[ ( x - a ) ^ { 2 } + b \right]$.\\

The functions $f$ and $g$ are defined by

$$\begin{aligned}
& \mathrm { f } ( x ) = x ^ { 2 } \quad \text { for } x \in \mathbb { R } \\
& \mathrm {~g} ( x ) = 2 x ^ { 2 } - 8 x + 14 \quad \text { for } x \in \mathbb { R }
\end{aligned}$$
\item Describe fully a sequence of transformations that maps the graph of $y = \mathrm { f } ( x )$ onto the graph of $y = \mathrm { g } ( x )$, making clear the order in which the transformations are applied.\\

\includegraphics[max width=\textwidth, alt={}, center]{05e75fa2-81ae-44b1-b073-4100f5d911e0-08_679_1043_260_552}

The circle with equation $( x + 1 ) ^ { 2 } + ( y - 2 ) ^ { 2 } = 85$ and the straight line with equation $y = 3 x - 20$ are shown in the diagram. The line intersects the circle at $A$ and $B$, and the centre of the circle is at $C$.
\end{enumerate}

\hfill \mbox{\textit{CAIE P1 2022 Q5 [6]}}