Hope someone can help me out here.. I've found the eigenvalues (lamda) of this matrix, but through a very very long way, does anyone know of a quicker way (there must be a quicker way). The matrix is 3x3:(adsbygoogle = window.adsbygoogle || []).push({});

H = ( E, a, a; a, E, a; a, a, E ).

I can reduce the determinant to the following, but still troublesome:

det(H) = | E - lamda, a, a; a, E - lamda, a; a, a, E - lamda |

det(H) = | E - lamda - a, a - E + lamda, 0; 0, E - lamda - a, a - E + lamda; a, a, E - lamda |

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# Determinant of this special matrix

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