8.
$$\mathbf { A } = \left( \begin{array} { r r r }
5 & - 2 & 5
0 & 3 & p
- 6 & 6 & - 4
\end{array} \right) \quad \text { where } p \text { is a constant }$$
Given that \(\left( \begin{array} { r } 2
1
- 2 \end{array} \right)\) is an eigenvector for \(\mathbf { A }\)
- determine the eigenvalue corresponding to this eigenvector
- hence show that \(p = 2\)
- determine the remaining eigenvalues and corresponding eigenvectors of \(\mathbf { A }\)
- Write down a matrix \(\mathbf { P }\) and a diagonal matrix \(\mathbf { D }\) such that \(\mathbf { A } = \mathbf { P D P } ^ { - 1 }\)
- Solve the differential equation \(\dot { u } = k u\), where \(k\) is a constant.
With respect to a fixed origin \(O\), the velocity of a particle moving through space is modelled by
$$\left( \begin{array} { c }
\dot { x }
\dot { y }
\dot { z }
\end{array} \right) = \mathbf { A } \left( \begin{array} { l }
x
y
z
\end{array} \right)$$
By considering \(\left( \begin{array} { c } u
v
w \end{array} \right) = \mathbf { P } ^ { - 1 } \left( \begin{array} { c } x
y
z \end{array} \right)\) so that \(\left( \begin{array} { c } \dot { u }
\dot { v }
\dot { w } \end{array} \right) = \mathbf { P } ^ { - 1 } \left( \begin{array} { c } \dot { x }
\dot { y }
\dot { z } \end{array} \right)\) - determine a general solution for the displacement of the particle.