Question 1309

Vectors II: Lines and Planes
2009 Paper 1 Question 10 Variant

Question

The planes p1{p_1} and p2{p_2} have equations r(123)=2{\mathbf{r} \cdot \begin{pmatrix} 1 \\ 2 \\ - 3 \end{pmatrix} = 2} and r(210)=2{\mathbf{r} \cdot \begin{pmatrix} - 2 \\ 1 \\ 0 \end{pmatrix} = 2} respectively, and meet in a line l.{l.}
(i)
Find the acute angle between p1{p_1} and p2.{p_2.}
[3]
(ii)
Find a vector equation of l.{l.}
[4]
(iii)
The plane p3{p_3} has equation
x+2y3z2+k(2x+y2)=0.{x + 2 y - 3 z - 2} + {k(- 2 x + y - 2)} = 0.
Explain why l{l} lies in p3{p_3} for any constant k.{k.}
Hence, or otherwise, find a cartesian equation of the plane in which both l{l} and the point (3,1,3){\left( - 3, - 1, 3 \right)} lie.
[5]

Answer