Back to An introduction to eigenvalues and eigenvectors

Exercise 2

Avg difficulty 2.5

Consider the matrix and vectors A=[−5−222414−102114−10],v1=[1−2−1],v2=[2−30],v3=[0−1−1]A = \left[\begin{array}{rrr} -5 & -2 & 2 \\ 24 & 14 & -10 \\ 21 & 14 & -10 \\ \end{array}\right],\qquad \vvec_1=\threevec{1}{-2}{-1}, \vvec_2=\threevec{2}{-3}{0}, \vvec_3=\threevec{0}{-1}{-1}

  1. Show that the vectors v1\vvec_1, v2\vvec_2, and v3\vvec_3 are eigenvectors of AA and find their associated eigenvalues.

  2. Express the vector x=[0−3−4]\xvec = \threevec{0}{-3}{-4} as a linear combination of the eigenvectors.

  3. Use this expression to compute AxA\xvec, A2xA^2\xvec, and A−1xA^{-1}\xvec as a linear combination of eigenvectors.

Austin, Understanding Linear Algebra, §4.1 An introduction to eigenvalues and eigenvectors, Exercise 2

AI Tutor

Adapted from Understanding Linear Algebra © 2023 David Austin. Licensed under CC BY 4.0. Source: Understanding Linear Algebra. Imported at revision 3e6dced.