OCR MEI FP2 2007 January — Question 3

Exam BoardOCR MEI
ModuleFP2 (Further Pure Mathematics 2)
Year2007
SessionJanuary
Topic3x3 Matrices

3 Let \(\mathbf { P } = \left( \begin{array} { r r r } 4 & 2 & k
1 & 1 & 3
1 & 0 & - 1 \end{array} \right) (\) where \(k \neq 4 )\) and \(\mathbf { M } = \left( \begin{array} { r r r } 2 & - 2 & - 6
- 1 & 3 & 1
1 & - 2 & - 2 \end{array} \right)\).
  1. Find \(\mathbf { P } ^ { - 1 }\) in terms of \(k\), and show that, when \(k = 2 , \mathbf { P } ^ { - 1 } = \frac { 1 } { 2 } \left( \begin{array} { r r r } - 1 & 2 & 4
    4 & - 6 & - 10
    - 1 & 2 & 2 \end{array} \right)\).
  2. Verify that \(\left( \begin{array} { l } 4
    1
    1 \end{array} \right) , \left( \begin{array} { l } 2
    1
    0 \end{array} \right)\) and \(\left( \begin{array} { r } 2
    3
    - 1 \end{array} \right)\) are eigenvectors of \(\mathbf { M }\), and find the corresponding eigenvalues.
  3. Show that \(\mathbf { M } ^ { n } = \left( \begin{array} { r r r } 4 & - 6 & - 10
    2 & - 3 & - 5
    0 & 0 & 0 \end{array} \right) + 2 ^ { n - 1 } \left( \begin{array} { r r r } - 2 & 4 & 4
    - 3 & 6 & 6
    1 & - 2 & - 2 \end{array} \right)\). Section B (18 marks)