$\begin{bmatrix} 0 & 1 & 1 \\ 1 & 0 & 1 \\ 1& 1 & 0 \\ \end{bmatrix}$
trying to understand how to find Eigen value and vector by inspection for symmetry matrix
$\begin{bmatrix}
0 & 1 & 1 \\
1 & 0 & 1 \\
1& 1 & 0 \\
\end{bmatrix}$
as the matrix has trace $0$, which mean sum of eigen values is zero.
and sum up each number in row produce 2 which mean 2 is one of Eigen value.
beside how can I find another Eigen vector by inspection?
and also the other one Eigen value is $-1$ but with geometry multiplicity two. how can I find it using inspection?