Question 9

Math Analysis HL Paper 2 (May 2025, TZ2)

  1. [Maximum mark: 8]

A line (L_1) has vector equation (\mathbf{r} = \begin{pmatrix} 0 \ 0 \ 2 \end{pmatrix} + t \begin{pmatrix} 1 \ 0 \ 1 \end{pmatrix}) where (t \in \mathbb{R}).

The plane (\Pi_1) contains the line (L_1) and passes through the point (2, 1, 5).

(a) Show that the Cartesian equation of the plane (\Pi_1) is (x + y - z = -2). [4]

Consider the three planes:

Equations of three planes: Π1: x+y-z=-2, Π2: 2x+by-z=3, Π3: x-y+2z=d.
Equations of three planes: Π1: x+y-z=-2, Π2: 2x+by-z=3, Π3: x-y+2z=d.

(\Pi_1: x + y - z = -2)
(\Pi_2: 2x + by - z = 3)
(\Pi_3: x - y + 2z = d)
where (b, d \in \mathbb{Q}^+).

The three planes intersect in a line.

(b) Find the value of (b) and the value of (d). [4]