AQA C4 2011 June — Question 5 12 marks

Exam BoardAQA
ModuleC4 (Core Mathematics 4)
Year2011
SessionJune
Marks12
PaperDownload PDF ↗
TopicVectors 3D & Lines
TypeShow lines intersect and find intersection point
DifficultyStandard +0.3 This is a standard multi-part vectors question requiring routine techniques: finding a line equation from two points, solving simultaneous equations for intersection, and using perpendicularity conditions. While it has multiple parts (5+ marks total), each step follows textbook methods without requiring novel insight or particularly complex algebraic manipulation. Slightly above average difficulty due to the 3D context and multi-step nature, but well within the scope of standard C4 examination questions.
Spec1.10a Vectors in 2D: i,j notation and column vectors1.10b Vectors in 3D: i,j,k notation1.10c Magnitude and direction: of vectors1.10d Vector operations: addition and scalar multiplication1.10e Position vectors: and displacement1.10f Distance between points: using position vectors4.04a Line equations: 2D and 3D, cartesian and vector forms4.04c Scalar product: calculate and use for angles4.04e Line intersections: parallel, skew, or intersecting

5 The points \(A\) and \(B\) have coordinates \(( 5,1 , - 2 )\) and \(( 4 , - 1,3 )\) respectively.
The line \(l\) has equation \(\mathbf { r } = \left[ \begin{array} { r } - 8 \\ 5 \\ - 6 \end{array} \right] + \mu \left[ \begin{array} { r } 5 \\ 0 \\ - 2 \end{array} \right]\).
  1. Find a vector equation of the line that passes through \(A\) and \(B\).
    1. Show that the line that passes through \(A\) and \(B\) intersects the line \(l\), and find the coordinates of the point of intersection, \(P\).
    2. The point \(C\) lies on \(l\) such that triangle \(P B C\) has a right angle at \(B\). Find the coordinates of \(C\).

5 The points $A$ and $B$ have coordinates $( 5,1 , - 2 )$ and $( 4 , - 1,3 )$ respectively.\\
The line $l$ has equation $\mathbf { r } = \left[ \begin{array} { r } - 8 \\ 5 \\ - 6 \end{array} \right] + \mu \left[ \begin{array} { r } 5 \\ 0 \\ - 2 \end{array} \right]$.
\begin{enumerate}[label=(\alph*)]
\item Find a vector equation of the line that passes through $A$ and $B$.
\item \begin{enumerate}[label=(\roman*)]
\item Show that the line that passes through $A$ and $B$ intersects the line $l$, and find the coordinates of the point of intersection, $P$.
\item The point $C$ lies on $l$ such that triangle $P B C$ has a right angle at $B$. Find the coordinates of $C$.
\end{enumerate}\end{enumerate}

\hfill \mbox{\textit{AQA C4 2011 Q5 [12]}}