Question 1311

Vectors II: Lines and Planes
2011 Paper 1 Question 11 Variant

Question

The plane p{p} passes through the points with coordinates (12,5,4),{\left( - 12, 5, - 4 \right),} (2,2,4){\left( 2, - 2, - 4 \right)} (8,5,5).{\left( 8, - 5, - 5 \right).}
(i)
Find a cartesian equation of p.{p.}
[4]
The line l1{l_1} has equation
x+64=y22=z+63\frac{x + 6}{4} = \frac{y - 2}{-2} = \frac{z + 6}{-3}
and the line l2{l_2} has equation
x82=y+113=z+21k,\frac{x - 8}{- 2} = \frac{y + 11}{3} = \frac{z + 21}{k},
where k{k} is a constant. It is given that l1{l_1} and l2{l_2} intersect.
(ii)
Find the value of k.{k.}
[4]
(iii)
Show that l1{l_1} lies in p{p} and find the coordinates of the point at which l2{l_2} intersects p.{p.}
[4]
(iv)
Find the acute angle between l2{l_2} and p.{p.}
[3]

Answer