Question 1311

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

Question

The plane p{p} passes through the points with coordinates (1,4,2),{\left( 1, - 4, 2 \right),} (0,2,8){\left( 0, 2, - 8 \right)} (3,9,8).{\left( 3, - 9, 8 \right).}
(i)
Find a cartesian equation of p.{p.}
[4]
The line l1{l_1} has equation
x72=y+113=z42\frac{x - 7}{-2} = \frac{y + 11}{3} = \frac{z - 4}{-2}
and the line l2{l_2} has equation
x+75=y+282=z18k,\frac{x + 7}{- 5} = \frac{y + 28}{- 2} = \frac{z - 18}{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