Edexcel F1 2015 January — Question 4 14 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2015
SessionJanuary
Marks14
PaperDownload PDF ↗
TopicConic sections
TypeParabola normal intersection problems
DifficultyChallenging +1.2 This is a standard Further Maths parabola question requiring parametric differentiation, normal equation derivation, solving a cubic for intersection points, and triangle area calculation. While it involves multiple steps and Further Maths content (making it harder than typical A-level), the techniques are routine for F1 students with no novel problem-solving required.
Spec1.03d Circles: equation (x-a)^2+(y-b)^2=r^21.03e Complete the square: find centre and radius of circle1.03f Circle properties: angles, chords, tangents1.03g Parametric equations: of curves and conversion to cartesian1.07m Tangents and normals: gradient and equations

4. The parabola \(C\) has cartesian equation \(y ^ { 2 } = 12 x\) The point \(P \left( 3 p ^ { 2 } , 6 p \right)\) lies on \(C\), where \(p \neq 0\)
  1. Show that the equation of the normal to the curve \(C\) at the point \(P\) is $$y + p x = 6 p + 3 p ^ { 3 }$$ This normal crosses the curve \(C\) again at the point \(Q\).
    Given that \(p = 2\) and that \(S\) is the focus of the parabola, find
  2. the coordinates of the point \(Q\),
  3. the area of the triangle \(P Q S\).

4. The parabola $C$ has cartesian equation $y ^ { 2 } = 12 x$

The point $P \left( 3 p ^ { 2 } , 6 p \right)$ lies on $C$, where $p \neq 0$
\begin{enumerate}[label=(\alph*)]
\item Show that the equation of the normal to the curve $C$ at the point $P$ is

$$y + p x = 6 p + 3 p ^ { 3 }$$

This normal crosses the curve $C$ again at the point $Q$.\\
Given that $p = 2$ and that $S$ is the focus of the parabola, find
\item the coordinates of the point $Q$,
\item the area of the triangle $P Q S$.
\end{enumerate}

\hfill \mbox{\textit{Edexcel F1 2015 Q4 [14]}}