Find eigenvalues of matrix:
$$ A = \left[ \begin{matrix}10&2&1\\2&10&3\\1&3&10\end{matrix} \right] $$The eigenvalues of matrix A are:
$$ $$Step 1 : The characteristic polynomial for matrix A is:
$$ p(\lambda) = -\lambda^3+30\lambda^2-286\lambda+872 $$
Step 2 : Eigenvalues are roots of the characteristic polynomial, so the equation
$$ -\lambda^3+30\lambda^2-286\lambda+872 = 0 $$yields the above eigenvalues.
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