Edexcel F3 2023 January — Question 5

Exam BoardEdexcel
ModuleF3 (Further Pure Mathematics 3)
Year2023
SessionJanuary
Topic3x3 Matrices

5. $$\mathbf { A } = \left( \begin{array} { r r r } a & a & 1
- a & 4 & 0
4 & a & 5 \end{array} \right) \quad \text { where } a \text { is a positive constant }$$
  1. Determine the exact value of \(a\) for which the matrix \(\mathbf { A }\) is singular. Given that 2 is an eigenvalue of \(\mathbf { A }\)
  2. determine
    1. the value of \(a\)
    2. the other two eigenvalues of \(\mathbf { A }\) A normalised eigenvector for the eigenvalue 2 is \(\left( \begin{array} { c } \frac { 1 } { \sqrt { 6 } }
      \frac { 1 } { \sqrt { 6 } }
      - \frac { 2 } { \sqrt { 6 } } \end{array} \right)\)
  3. Determine a normalised eigenvector for each of the other eigenvalues of \(\mathbf { A }\)
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