Edexcel AEA 2010 June — Question 4 16 marks

Exam BoardEdexcel
ModuleAEA (Advanced Extension Award)
Year2010
SessionJune
Marks16
PaperDownload PDF ↗
TopicVectors: Lines & Planes
TypeLine intersection with line
DifficultyChallenging +1.2 This is a structured 3D vectors question with standard techniques: (a) uses dot product for angle between vectors, (b) requires perpendicular projection onto a line, (c) involves finding line intersection by equating parametric forms. While it requires multiple steps and careful coordinate work, all techniques are standard A-level Further Maths content with no novel insights needed. The cuboid setup makes visualization straightforward. Slightly above average due to the 3D context and multi-part nature, but well within typical AEA difficulty.
Spec4.04c Scalar product: calculate and use for angles4.04d Angles: between planes and between line and plane4.04e Line intersections: parallel, skew, or intersecting4.04f Line-plane intersection: find point

4. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{0396f61a-b844-40ed-98d1-82ee2d8a6807-3_643_332_246_870} \captionsetup{labelformat=empty} \caption{Figure 1}
\end{figure} Figure 1 shows a cuboid \(O A B C D E F G\), where \(O\) is the origin, \(A\) has position vector \(5 \mathbf { i } , C\) has position vector \(10 \mathbf { j }\) and \(D\) has position vector \(20 \mathbf { k }\).
  1. Find the cosine of angle \(C A F\). Given that the point \(X\) lies on \(A C\) and that \(F X\) is perpendicular to \(A C\),
  2. find the position vector of point \(X\) and the distance \(F X\). The line \(l _ { 1 }\) passes through \(O\) and through the midpoint of the face \(A B F E\). The line \(l _ { 2 }\) passes through \(A\) and through the midpoint of the edge \(F G\).
  3. Show that \(l _ { 1 }\) and \(l _ { 2 }\) intersect and find the coordinates of the point of intersection.

4.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{0396f61a-b844-40ed-98d1-82ee2d8a6807-3_643_332_246_870}
\captionsetup{labelformat=empty}
\caption{Figure 1}
\end{center}
\end{figure}

Figure 1 shows a cuboid $O A B C D E F G$, where $O$ is the origin, $A$ has position vector $5 \mathbf { i } , C$ has position vector $10 \mathbf { j }$ and $D$ has position vector $20 \mathbf { k }$.
\begin{enumerate}[label=(\alph*)]
\item Find the cosine of angle $C A F$.

Given that the point $X$ lies on $A C$ and that $F X$ is perpendicular to $A C$,
\item find the position vector of point $X$ and the distance $F X$.

The line $l _ { 1 }$ passes through $O$ and through the midpoint of the face $A B F E$. The line $l _ { 2 }$ passes through $A$ and through the midpoint of the edge $F G$.
\item Show that $l _ { 1 }$ and $l _ { 2 }$ intersect and find the coordinates of the point of intersection.
\end{enumerate}

\hfill \mbox{\textit{Edexcel AEA 2010 Q4 [16]}}