Edexcel FP1 2009 January — Question 3 4 marks

Exam BoardEdexcel
ModuleFP1 (Further Pure Mathematics 1)
Year2009
SessionJanuary
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicConic sections
TypeParametric point verification
DifficultyModerate -0.8 This is a straightforward Further Maths question requiring basic parametric-to-Cartesian conversion (eliminating t to get xy=25) and simple coordinate substitution to find two points then their midpoint. While it's from FP1, the techniques are routine with no problem-solving or insight required—just mechanical application of standard methods.
Spec1.03g Parametric equations: of curves and conversion to cartesian

3. The rectangular hyperbola, \(H\), has parametric equations \(x = 5 t , y = \frac { 5 } { t } , t \neq 0\).
  1. Write the cartesian equation of \(H\) in the form \(x y = c ^ { 2 }\). Points \(A\) and \(B\) on the hyperbola have parameters \(t = 1\) and \(t = 5\) respectively.
  2. Find the coordinates of the mid-point of \(A B\).

Question 3:
Part (a)
AnswerMarks Guidance
Answer/WorkingMarks Guidance
\(xy = 25 = 5^2\) or \(c = \pm 5\)B1 \(xy=25\) only B1; \(c^2=25\) only B1; \(c=5\) only B1
Part (b)
AnswerMarks Guidance
Answer/WorkingMarks Guidance
\(A\) has co-ords \((5,5)\) and \(B\) has co-ords \((25,1)\)B1 Both coordinates required for B1
Mid point is at \((15, 3)\)M1 A1 Add coordinates and divide by 2 on both for M1
## Question 3:

### Part (a)

| Answer/Working | Marks | Guidance |
|---|---|---|
| $xy = 25 = 5^2$ or $c = \pm 5$ | B1 | $xy=25$ only B1; $c^2=25$ only B1; $c=5$ only B1 |

### Part (b)

| Answer/Working | Marks | Guidance |
|---|---|---|
| $A$ has co-ords $(5,5)$ and $B$ has co-ords $(25,1)$ | B1 | Both coordinates required for B1 |
| Mid point is at $(15, 3)$ | M1 A1 | Add coordinates and divide by 2 on both for M1 |

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3. The rectangular hyperbola, $H$, has parametric equations $x = 5 t , y = \frac { 5 } { t } , t \neq 0$.
\begin{enumerate}[label=(\alph*)]
\item Write the cartesian equation of $H$ in the form $x y = c ^ { 2 }$.

Points $A$ and $B$ on the hyperbola have parameters $t = 1$ and $t = 5$ respectively.
\item Find the coordinates of the mid-point of $A B$.
\end{enumerate}

\hfill \mbox{\textit{Edexcel FP1 2009 Q3 [4]}}