AQA FP1 2009 June — Question 6 11 marks

Exam BoardAQA
ModuleFP1 (Further Pure Mathematics 1)
Year2009
SessionJune
Marks11
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicConic sections
TypeConic translation and transformation
DifficultyStandard +0.3 This is a straightforward multi-part question on standard ellipse transformations. Part (a) requires basic sketching and finding intercepts by substitution. Part (b) involves applying a simple stretch transformation rule. Part (c) requires completing the square (a routine FP1 technique) to identify the translation vector. All parts follow standard procedures with no novel problem-solving required, making it slightly easier than average.
Spec1.02n Sketch curves: simple equations including polynomials1.02w Graph transformations: simple transformations of f(x)1.03d Circles: equation (x-a)^2+(y-b)^2=r^2

6 An ellipse \(E\) has equation $$\frac { x ^ { 2 } } { 3 } + \frac { y ^ { 2 } } { 4 } = 1$$
  1. Sketch the ellipse \(E\), showing the coordinates of the points of intersection of the ellipse with the coordinate axes.
  2. The ellipse \(E\) is stretched with scale factor 2 parallel to the \(y\)-axis. Find and simplify the equation of the curve after the stretch.
  3. The original ellipse, \(E\), is translated by the vector \(\left[ \begin{array} { l } a \\ b \end{array} \right]\). The equation of the translated ellipse is $$4 x ^ { 2 } + 3 y ^ { 2 } - 8 x + 6 y = 5$$ Find the values of \(a\) and \(b\).

Question 6:
Part (a):
AnswerMarks Guidance
AnswerMark Guidance
Correct ellipse shape drawnB1 Must be closed curve
\((0, 2)\) and \((0, -2)\) marked on y-axisB1 Accept \(y\)-intercepts \(\pm 2\)
\((\sqrt{3}, 0)\) and \((-\sqrt{3}, 0)\) marked on x-axisB1 Accept \(x\)-intercepts \(\pm\sqrt{3}\)
Part (b):
AnswerMarks Guidance
AnswerMark Guidance
Replacement \(y \to \frac{y}{2}\) usedM1 Scale factor 2 parallel to \(y\)-axis means replace \(y\) with \(\frac{y}{2}\)
\(\frac{x^2}{3} + \frac{y^2}{16} = 1\)A1
Simplified to \(16x^2 + 3y^2 = 48\) or equivalentA1 Must be simplified
Part (c):
AnswerMarks Guidance
AnswerMark Guidance
Complete the square or expand translation: replace \(x\) with \((x-a)\), \(y\) with \((y-b)\)M1
\(\frac{(x-a)^2}{3} + \frac{(y-b)^2}{4} = 1\) expandedM1
Comparing \(4x^2 + 3y^2 - 8x + 6y = 5\): factor out to get \(4(x^2 - 2x) + 3(y^2 + 2y) = 5\)M1
\(4(x-1)^2 - 4 + 3(y+1)^2 - 3 = 5 \Rightarrow \frac{(x-1)^2}{3} + \frac{(y+1)^2}{4} = 1\)A1
\(a = 1, \quad b = -1\)A1 Both correct
# Question 6:

## Part (a):
| Answer | Mark | Guidance |
|--------|------|----------|
| Correct ellipse shape drawn | B1 | Must be closed curve |
| $(0, 2)$ and $(0, -2)$ marked on y-axis | B1 | Accept $y$-intercepts $\pm 2$ |
| $(\sqrt{3}, 0)$ and $(-\sqrt{3}, 0)$ marked on x-axis | B1 | Accept $x$-intercepts $\pm\sqrt{3}$ |

## Part (b):
| Answer | Mark | Guidance |
|--------|------|----------|
| Replacement $y \to \frac{y}{2}$ used | M1 | Scale factor 2 parallel to $y$-axis means replace $y$ with $\frac{y}{2}$ |
| $\frac{x^2}{3} + \frac{y^2}{16} = 1$ | A1 | |
| Simplified to $16x^2 + 3y^2 = 48$ or equivalent | A1 | Must be simplified |

## Part (c):
| Answer | Mark | Guidance |
|--------|------|----------|
| Complete the square or expand translation: replace $x$ with $(x-a)$, $y$ with $(y-b)$ | M1 | |
| $\frac{(x-a)^2}{3} + \frac{(y-b)^2}{4} = 1$ expanded | M1 | |
| Comparing $4x^2 + 3y^2 - 8x + 6y = 5$: factor out to get $4(x^2 - 2x) + 3(y^2 + 2y) = 5$ | M1 | |
| $4(x-1)^2 - 4 + 3(y+1)^2 - 3 = 5 \Rightarrow \frac{(x-1)^2}{3} + \frac{(y+1)^2}{4} = 1$ | A1 | |
| $a = 1, \quad b = -1$ | A1 | Both correct |

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6 An ellipse $E$ has equation

$$\frac { x ^ { 2 } } { 3 } + \frac { y ^ { 2 } } { 4 } = 1$$
\begin{enumerate}[label=(\alph*)]
\item Sketch the ellipse $E$, showing the coordinates of the points of intersection of the ellipse with the coordinate axes.
\item The ellipse $E$ is stretched with scale factor 2 parallel to the $y$-axis.

Find and simplify the equation of the curve after the stretch.
\item The original ellipse, $E$, is translated by the vector $\left[ \begin{array} { l } a \\ b \end{array} \right]$. The equation of the translated ellipse is

$$4 x ^ { 2 } + 3 y ^ { 2 } - 8 x + 6 y = 5$$

Find the values of $a$ and $b$.
\end{enumerate}

\hfill \mbox{\textit{AQA FP1 2009 Q6 [11]}}