4.
$$\mathbf { M } = \left( \begin{array} { l l l }
1 & 1 & 3
1 & 5 & 1
3 & 1 & 1
\end{array} \right)$$
- Show that 6 is an eigenvalue of the matrix \(\mathbf { M }\) and find the other two eigenvalues of \(\mathbf { M }\).
- Find a normalised eigenvector corresponding to the eigenvalue 6