Edexcel F3 2022 June — Question 3

Exam BoardEdexcel
ModuleF3 (Further Pure Mathematics 3)
Year2022
SessionJune
TopicInvariant lines and eigenvalues and vectors

3. $$\mathbf { M } = \left( \begin{array} { r r r } - 2 & 5 & 0
5 & 1 & - 3
0 & - 3 & 6 \end{array} \right)$$ Given that \(\mathbf { i } + \mathbf { j } + \mathbf { k }\) is an eigenvector of \(\mathbf { M }\),
  1. determine the corresponding eigenvalue. Given that 8 is an eigenvalue of \(\mathbf { M }\),
  2. determine a corresponding eigenvector.
  3. Determine a diagonal matrix \(\mathbf { D }\) and an orthogonal matrix \(\mathbf { P }\) such that $$\mathbf { D } = \mathbf { P } ^ { \mathrm { T } } \mathbf { M P }$$