Edexcel FP1 — Question 8 10 marks

Exam BoardEdexcel
ModuleFP1 (Further Pure Mathematics 1)
Marks10
PaperDownload PDF ↗
TopicConic sections
TypeParabola tangent intersection problems
DifficultyStandard +0.3 This is a structured multi-part question on parabola properties using parametric form. Part (a) requires implicit differentiation and substitution (standard technique), parts (b-d) involve straightforward coordinate geometry. While it's a Further Maths topic, the question guides students through each step with no novel insight required—slightly easier than average A-level difficulty overall.
Spec1.03g Parametric equations: of curves and conversion to cartesian1.07s Parametric and implicit differentiation

A parabola has equation \(y^2 = 4ax\), \(a > 0\). The point \(Q (aq^2, 2aq)\) lies on the parabola.
  1. Show that an equation of the tangent to the parabola at \(Q\) is $$yq = x + aq^2.$$ [4]
  2. This tangent meets the \(y\)-axis at the point \(R\). Find an equation of the line \(l\) which passes through \(R\) and is perpendicular to the tangent at \(Q\). [3]
  3. Show that \(l\) passes through the focus of the parabola. [1]
  4. Find the coordinates of the point where \(l\) meets the directrix of the parabola. [2]

A parabola has equation $y^2 = 4ax$, $a > 0$. The point $Q (aq^2, 2aq)$ lies on the parabola.

\begin{enumerate}[label=(\alph*)]
\item Show that an equation of the tangent to the parabola at $Q$ is
$$yq = x + aq^2.$$
[4]

\item This tangent meets the $y$-axis at the point $R$.

Find an equation of the line $l$ which passes through $R$ and is perpendicular to the tangent at $Q$.
[3]

\item Show that $l$ passes through the focus of the parabola.
[1]

\item Find the coordinates of the point where $l$ meets the directrix of the parabola.
[2]
\end{enumerate}

\hfill \mbox{\textit{Edexcel FP1  Q8 [10]}}