OCR MEI FP2 2014 June — Question 3

Exam BoardOCR MEI
ModuleFP2 (Further Pure Mathematics 2)
Year2014
SessionJune
TopicInvariant lines and eigenvalues and vectors

3
    1. Find the eigenvalues and corresponding eigenvectors for the matrix \(\mathbf { A }\), where $$\mathbf { A } = \left( \begin{array} { l l } 6 & - 3
      4 & - 1 \end{array} \right)$$
    2. Write down a matrix \(\mathbf { P }\) and a diagonal matrix \(\mathbf { D }\) such that \(\mathbf { A } = \mathbf { P D P } ^ { - 1 }\).
    1. The \(3 \times 3\) matrix \(\mathbf { B }\) has characteristic equation $$\lambda ^ { 3 } - 4 \lambda ^ { 2 } - 3 \lambda - 10 = 0$$ Show that 5 is an eigenvalue of \(\mathbf { B }\). Show that \(\mathbf { B }\) has no other real eigenvalues.
    2. An eigenvector corresponding to the eigenvalue 5 is \(\left( \begin{array} { r } - 2
      1
      4 \end{array} \right)\). Evaluate \(\mathbf { B } \left( \begin{array} { r } - 2
      1
      4 \end{array} \right)\) and \(\mathbf { B } ^ { 2 } \left( \begin{array} { r } 4
      - 2
      - 8 \end{array} \right)\).
      Solve the equation \(\mathbf { B } \left( \begin{array} { l } x
      y
      z \end{array} \right) = \left( \begin{array} { r } - 20
      10
      40 \end{array} \right)\) for \(x , y , z\).
    3. Show that \(\mathbf { B } ^ { 4 } = 19 \mathbf { B } ^ { 2 } + 22 \mathbf { B } + 40 \mathbf { I }\).