Edexcel F1 2018 January — Question 6 12 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2018
SessionJanuary
Marks12
PaperDownload PDF ↗
TopicConic sections
TypeParabola tangent equation derivation
DifficultyStandard +0.3 This is a straightforward Further Maths question testing standard parabola properties (focus, directrix) and routine calculus for finding tangent equations. Part (c) explicitly asks to 'show' a given result using differentiation, making it mechanical verification rather than problem-solving. Part (d) requires solving simultaneous equations with a hyperbola, which is routine algebraic manipulation. While it's a multi-part question worth several marks, each component uses standard techniques without requiring novel insight—slightly easier than average even for Further Maths.
Spec1.03h Parametric equations: in modelling contexts1.07s Parametric and implicit differentiation

  1. The parabola \(C\) has equation \(y ^ { 2 } = 32 x\) and the point \(S\) is the focus of this parabola. The point \(P ( 2,8 )\) lies on \(C\) and the point \(T\) lies on the directrix of \(C\). The line segment \(P T\) is parallel to the \(x\)-axis.
    1. Write down the coordinates of \(S\).
    2. Find the length of \(P T\).
    3. Using calculus, show that the tangent to \(C\) at the point \(P\) has equation
    $$y = 2 x + 4$$ The hyperbola \(H\) has equation \(x y = 4\). The tangent to \(C\) at \(P\) meets \(H\) at the points \(L\) and \(M\).
  2. Find the exact coordinates of the points \(L\) and \(M\), giving your answers in their simplest form.

\begin{enumerate}
  \item The parabola $C$ has equation $y ^ { 2 } = 32 x$ and the point $S$ is the focus of this parabola. The point $P ( 2,8 )$ lies on $C$ and the point $T$ lies on the directrix of $C$. The line segment $P T$ is parallel to the $x$-axis.\\
(a) Write down the coordinates of $S$.\\
(b) Find the length of $P T$.\\
(c) Using calculus, show that the tangent to $C$ at the point $P$ has equation
\end{enumerate}

$$y = 2 x + 4$$

The hyperbola $H$ has equation $x y = 4$. The tangent to $C$ at $P$ meets $H$ at the points $L$ and $M$.\\
(d) Find the exact coordinates of the points $L$ and $M$, giving your answers in their simplest form.\\

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\hfill \mbox{\textit{Edexcel F1 2018 Q6 [12]}}