Find all of the eigenvalues λ of the matrix A. (Hint: Use the method of Example 4.5 of finding the solutions to the equation 0 = det(A − λI). Enter your answers as a comma-separated list.) A = 3 5 8 0

Respuesta :

Answer:

[tex]\lambda=8,\ \lambda=-5[/tex]

Step-by-step explanation:

Eigenvalues of a Matrix

Given a matrix A, the eigenvalues of A, called [tex]\lambda[/tex] are scalars who comply with the relation:

[tex]det(A-\lambda I)=0[/tex]

Where I is the identity matrix

[tex]I=\left[\begin{array}{cc}1&0\\0&1\end{array}\right][/tex]

The matrix is given as

[tex]A=\left[\begin{array}{cc}3&5\\8&0\end{array}\right][/tex]

Set up the equation to solve

[tex]det\left(\left[\begin{array}{cc}3&5\\8&0\end{array}\right]-\left[\begin{array}{cc}\lambda&0\\0&\lambda \end{array}\right]\right)=0[/tex]

Expanding the determinant

[tex]det\left(\left[\begin{array}{cc}3-\lambda&5\\8&-\lambda\end{array}\right]\right)=0[/tex]

[tex](3-\lambda)(-\lambda)-40=0[/tex]

Operating Rearranging

[tex]\lambda^2-3\lambda-40=0[/tex]

Factoring

[tex](\lambda-8)(\lambda+5)=0[/tex]

Solving, we have the eigenvalues

[tex]\boxed{\lambda=8,\ \lambda=-5}[/tex]