Example1. [8-62-67-42-43] Find eigenvalues ...
|A-λI|=0
|(8-λ)-62-6(7-λ)-42-4(3-λ)|=0
(8-λ)((7-λ)×(3-λ)-(-4)×(-4))-(-6)((-6)×(3-λ)-(-4)×2)+2((-6)×(-4)-(7-λ)×2)=0
(8-λ)((21-10λ+λ2)-16)+6((-18+6λ)-(-8))+2(24-(14-2λ))=0
(8-λ)(5-10λ+λ2)+6(-10+6λ)+2(10+2λ)=0
(40-85λ+18λ2-λ3)+(-60+36λ)+(20+4λ)=0
(-λ3+18λ2-45λ)=0
-λ(λ-3)(λ-15)=0
:. the eigenvalues of the matrix A are given by lamda=0,3,15
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