Ortogonally diagonalize the given matrix A, giving the diagonal matrix D and the diagonalizing orthogonal matrix P.

Find the eigenvalues using charactreistic polynomial For

[tex](-3I_3-A)=\left[ {\begin{array}{ccc}

-2 & -2 & -2 \\

-2 & -2 & -2 \\

-2 & -2 & -2 \\

\end{array} } \right]

\]

so this means the eigenvector is

for

so the eigvenvector for is (again)

I can't diagonalize a matrix with only one eigenvector, where am I going wrong?