Edexcel C4 2014 January — Question 8

Exam BoardEdexcel
ModuleC4 (Core Mathematics 4)
Year2014
SessionJanuary
TopicVectors 3D & Lines

8. With respect to a fixed origin \(O\), the lines \(l _ { 1 }\) and \(l _ { 2 }\) are given by the equations $$l _ { 1 } : \mathbf { r } = \left( \begin{array} { r } 2
- 3
4 \end{array} \right) + \lambda \left( \begin{array} { r } - 1
2
1 \end{array} \right) , \quad l _ { 2 } : \mathbf { r } = \left( \begin{array} { r } 2
- 3
4 \end{array} \right) + \mu \left( \begin{array} { r } 5
- 2
5 \end{array} \right)$$ where \(\lambda\) and \(\mu\) are scalar parameters.
  1. Find, to the nearest \(0.1 ^ { \circ }\), the acute angle between \(l _ { 1 }\) and \(l _ { 2 }\) The point \(A\) has position vector \(\left( \begin{array} { l } 0
    1
    6 \end{array} \right)\).
  2. Show that \(A\) lies on \(l _ { 1 }\) The lines \(l _ { 1 }\) and \(l _ { 2 }\) intersect at the point \(X\).
  3. Write down the coordinates of \(X\).
  4. Find the exact value of the distance \(A X\). The distinct points \(B _ { 1 }\) and \(B _ { 2 }\) both lie on the line \(l _ { 2 }\)
    Given that \(A X = X B _ { 1 } = X B _ { 2 }\)
  5. find the area of the triangle \(A B _ { 1 } B _ { 2 }\) giving your answer to 3 significant figures. Given that the \(x\) coordinate of \(B _ { 1 }\) is positive,
  6. find the exact coordinates of \(B _ { 1 }\) and the exact coordinates of \(B _ { 2 }\)
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