(a) If \(x = \begin{pmatrix} 2 \\ 3 \end{pmatrix}, y = \begin{pmatrix} 5 \\ -2 \end{pmatrix}\) and \(z = \begin{pmatrix} -4 \\ 13 \end{pmatrix}\), find the scalars p and q such that \(px + qy = z\).
(b)(i) Using the scale of 2cm to 2 units on both axis, draw on a graph paper two perpendicular axis x and y for \(-5 \leq x \leq 5, -5 \leq y \leq 5\) respectively.
(ii) Draw, on the graph paper, indicating clearly the vertices and their coordinates,
(1) the quadrilateral WXYZ with W(2, 3), X(4, -1), Y(-3, -4) and Z(-3, 2).
(2) the image \(W_{1}X_{1}Y_{1}Z_{1}\) of the quadrilateral WXYZ under an anti-clockwise rotation of 90° about the origin where \(W \to W_{1}, X \to X_{1}, Y \to Y_{1}\) and \(Z \to Z_{1}\).
(a) \(px + qy = z\) gives, component by component:
\[2p + 5q = -4 \quad (1) \qquad 3p - 2q = 13 \quad (2)\]
\((1) \times 2:\ 4p + 10q = -8\); \((2) \times 5:\ 15p - 10q = 65\). Adding: \(19p = 57 \Rightarrow p = 3\).
From (1): \(6 + 5q = -4 \Rightarrow q = -2\). So \(p = 3,\ q = -2\).
(b) A \(90^{\circ}\) anticlockwise rotation about the origin sends \((x, y) \to (-y, x)\):
- \(W(2, 3) \to W_1(-3, 2)\)
- \(X(4, -1) \to X_1(1, 4)\)
- \(Y(-3, -4) \to Y_1(4, -3)\)
- \(Z(-3, 2) \to Z_1(-2, -3)\)
Plot WXYZ and its image \(W_1 X_1 Y_1 Z_1\) on the axes drawn to the given scale, labelling each vertex with its coordinates.
(a) \(px + qy = z\) gives, component by component:
\[2p + 5q = -4 \quad (1) \qquad 3p - 2q = 13 \quad (2)\]
\((1) \times 2:\ 4p + 10q = -8\); \((2) \times 5:\ 15p - 10q = 65\). Adding: \(19p = 57 \Rightarrow p = 3\).
From (1): \(6 + 5q = -4 \Rightarrow q = -2\). So \(p = 3,\ q = -2\).
(b) A \(90^{\circ}\) anticlockwise rotation about the origin sends \((x, y) \to (-y, x)\):
- \(W(2, 3) \to W_1(-3, 2)\)
- \(X(4, -1) \to X_1(1, 4)\)
- \(Y(-3, -4) \to Y_1(4, -3)\)
- \(Z(-3, 2) \to Z_1(-2, -3)\)
Plot WXYZ and its image \(W_1 X_1 Y_1 Z_1\) on the axes drawn to the given scale, labelling each vertex with its coordinates.