SPS SPS FM 2020 June — Question 9

Exam BoardSPS
ModuleSPS FM (SPS FM)
Year2020
SessionJune
TopicInvariant lines and eigenvalues and vectors

9. $$\mathbf { A } = \left( \begin{array} { c c } k & - 2
1 - k & k \end{array} \right) \quad \text { where } k \text { is a constant }$$
  1. Show that the matrix \(\mathbf { A }\) is non-singular for all values of \(k\). A transformation \(T : \mathbb { R } ^ { 2 } \rightarrow \mathbb { R } ^ { 2 }\) is represented by the matrix \(\mathbf { A }\).
    The point \(P\) has position vector \(\binom { a } { 2 a }\) relative to an origin \(O\).
    The point \(Q\) has position vector \(\binom { 7 } { - 3 }\) relative to \(O\).
    Given that the point \(P\) is mapped onto the point \(Q\) under \(T\),
  2. determine the value of \(a\) and the value of \(k\). Given that, for a different value of \(k , T\) maps the line \(y = 2 x\) onto itself,
  3. determine this value of \(k\).