Question 1308

Vectors II: Lines and Planes
2008 Paper 1 Question 11 Variant

Question

The equations of three planes p1,{p_1, } p2,{p_2, } p3{p_3 } are
3x++3z=3,4x+8y4z=4,3x+λy5z=μ, \begin{alignat*}{6} - 3 x & \,+\, & & \,+\, & 3 z & = - 3, \\ - 4 x & \,+\, & 8 y & \,-\, & 4 z & = - 4, \\ 3 x & \,+\, & \lambda y & \,-\, & 5 z & = \mu, \end{alignat*}
respectively, where λ{\lambda} and μ{\mu} are constants.
When λ=19.3{\lambda=19.3} and μ=3,{\mu = 3,} find the coordinates of the point at which the three planes meet.
[2]
The planes p1{p_1} and p2{p_2} intersect in a line l.{l.}
(i)
Find a vector equation of l.{l.}
[4]
(ii)
Given that l{l} lies in p3,{p_3,} find λ{\lambda} and μ.{\mu.}
[3]
(iii)
Given instead that l{l} and p3{p_3} have no point in common, what can be said about the values of λ{\lambda} and μ.{\mu.}
[2]
(iv)
Find the cartesian equation of the plane which contains l{l} and the point (0,0,4).{\left( 0, 0, - 4 \right).}
[4]

Answer