(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Find the eigenvalues of:

|13 -30 0|

|1 0 0|

|0 1 0|

2. Relevant equations

Equation for the eigenvalues: det(A-λI)=0

Cofactor expansion = det A = a11(a22a33-a23a32)+a12(a23a31-a21a33)+a13(a21a32-a22a31)

3. The attempt at a solution

|13-λ -30 0 |

| 1 -λ 0 |

| 0 1 -λ|

(13 -λ)(λ[itex]^{2}[/itex])-30(-λ)+0 = 0

13λ[itex]^{2}[/itex]-λ[itex]^{3}[/itex]+30

-λ[itex]^{3}[/itex]+13λ[itex]^{2}[/itex]+ 30λ

-λ(λ[itex]^{2}[/itex]-13λ-30)

(λ+2)(λ-15)

Eigenvalues = 0, 2, 15

However, this not the correct answer according the the software I'm using. Can anyone see what I'm doing wrong?

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# Homework Help: Finding the eigenvalues of a 3x3

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