AQA FP1 2012 January — Question 7 12 marks

Exam BoardAQA
ModuleFP1 (Further Pure Mathematics 1)
Year2012
SessionJanuary
Marks12
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicConic sections
TypeConic translation and transformation
DifficultyStandard +0.3 This is a structured multi-part question on hyperbolas covering standard techniques: finding asymptotes (routine formula), sketching (basic visualization), applying translation (direct substitution), solving simultaneous equations (algebraic manipulation), and making a connection between translated and original curves. While it requires multiple steps and some algebraic care in part (c)(ii), each component uses well-practiced FP1 methods without requiring novel insight or particularly challenging problem-solving.
Spec1.02n Sketch curves: simple equations including polynomials1.02q Use intersection points: of graphs to solve equations1.02w Graph transformations: simple transformations of f(x)

7 A hyperbola \(H\) has equation $$\frac { x ^ { 2 } } { 9 } - y ^ { 2 } = 1$$
  1. Find the equations of the asymptotes of \(H\).
  2. The asymptotes of \(H\) are shown in the diagram opposite. On the same diagram, sketch the hyperbola \(H\). Indicate on your sketch the coordinates of the points of intersection of \(H\) with the coordinate axes.
  3. The hyperbola \(H\) is now translated by the vector \(\left[ \begin{array} { r } - 3 \\ 0 \end{array} \right]\).
    1. Write down the equation of the translated curve.
    2. Calculate the coordinates of the two points of intersection of the translated curve with the line \(y = x\).
  4. From your answers to part (c)(ii), deduce the coordinates of the points of intersection of the original hyperbola \(H\) with the line \(y = x - 3\). \includegraphics[max width=\textwidth, alt={}, center]{f9345653-d426-4350-bf1d-901506211078-4_675_1157_1932_495}

AnswerMarks Guidance
PartAnswer/Working Mark
(a)\(y = \pm\frac{1}{4}x\) B1
(b)2-branch curve with branches in correct regions above and below x-axis; Curve approaching asymptotes B1 B1
B1
(c)(i)\(\frac{(x+3)^2}{9} - y^2 = 1\) M1 A1
(c)(ii)\(\frac{(x+3)^2}{9} - x^2 = 1\) M1
\(x^2 + 6x + 9 = 9(x^2 + 1)\)A1F Correct expansion of \((x + 3)^2\) equated to \(9(x^2 + 1)\) OE ft; [OE in y]
\(8x^2 - 6x = 0\) (\(8x^2 = 6x\))A1F Ft on error (\(x - 3\)) for \((x + 3)\) in (c)(i) which gives \(8x^2 + 6x = 0\) (\(8x^2 = -6x\)) [OE in y]
Points are \((0, 0)\), \(\left(\frac{3}{4}, \frac{3}{4}\right)\)A1 4 marks; Both. ACF
(d) M1
Points are \((3, 0)\), \(\left(3\frac{3}{4}, -\frac{3}{4}\right)\)A1F 2 marks; Ft on c's (c)(ii) coordinates for the two points; If not deduced then M0A0
| Part | Answer/Working | Mark | Guidance |
|------|---|---|---|
| (a) | $y = \pm\frac{1}{4}x$ | B1 | 1 mark; ACF Need both |
| (b) | 2-branch curve with branches in correct regions above and below x-axis; Curve approaching asymptotes | B1 B1 | B1 B1 3 marks total; Coords $(\pm3, 0)$, as only points of intersection with coordinate axes, indicated. Condone −3 and +3 marked on x-axis at points of intersection as $(\pm3, 0)$ indicated |
| | | B1 | |
| (c)(i) | $\frac{(x+3)^2}{9} - y^2 = 1$ | M1 A1 | 2 marks; Replacing x by either $x + 3$ or $x - 3$ ACF |
| (c)(ii) | $\frac{(x+3)^2}{9} - x^2 = 1$ | M1 | Substitution into c's (c)(i) eqn of y = x to eliminate y or of x = y to eliminate x |
| | $x^2 + 6x + 9 = 9(x^2 + 1)$ | A1F | Correct expansion of $(x + 3)^2$ equated to $9(x^2 + 1)$ OE ft; [OE in y] |
| | $8x^2 - 6x = 0$ ($8x^2 = 6x$) | A1F | Ft on error ($x - 3$) for $(x + 3)$ in (c)(i) which gives $8x^2 + 6x = 0$ ($8x^2 = -6x$) [OE in y] |
| | Points are $(0, 0)$, $\left(\frac{3}{4}, \frac{3}{4}\right)$ | A1 | 4 marks; Both. ACF |
| (d) | | M1 | Adding 3 to c's (c)(ii) two x-coords keeping y-coordinates unchanged |
| | Points are $(3, 0)$, $\left(3\frac{3}{4}, -\frac{3}{4}\right)$ | A1F | 2 marks; Ft on c's (c)(ii) coordinates for the two points; If not deduced then M0A0 |
7 A hyperbola $H$ has equation

$$\frac { x ^ { 2 } } { 9 } - y ^ { 2 } = 1$$
\begin{enumerate}[label=(\alph*)]
\item Find the equations of the asymptotes of $H$.
\item The asymptotes of $H$ are shown in the diagram opposite. On the same diagram, sketch the hyperbola $H$. Indicate on your sketch the coordinates of the points of intersection of $H$ with the coordinate axes.
\item The hyperbola $H$ is now translated by the vector $\left[ \begin{array} { r } - 3 \\ 0 \end{array} \right]$.
\begin{enumerate}[label=(\roman*)]
\item Write down the equation of the translated curve.
\item Calculate the coordinates of the two points of intersection of the translated curve with the line $y = x$.
\end{enumerate}\item From your answers to part (c)(ii), deduce the coordinates of the points of intersection of the original hyperbola $H$ with the line $y = x - 3$.\\
\includegraphics[max width=\textwidth, alt={}, center]{f9345653-d426-4350-bf1d-901506211078-4_675_1157_1932_495}
\end{enumerate}

\hfill \mbox{\textit{AQA FP1 2012 Q7 [12]}}