Back to Finding eigenvectors numerically

Exercise 5

Avg difficulty 2.5

We have seen that the matrix A=[1221]A = \left[\begin{array}{rr} 1 & 2 \\ 2 & 1 \\ \end{array}\right] has eigenvalues λ1=3\lambda_1 = 3 and λ2=−1\lambda_2=-1 and associated eigenvectors v1=[11]\vvec_1 = \twovec{1}{1} and v2=[−11]\vvec_2=\twovec{-1}{1}.

  1. Describe what happens when we apply the inverse power method using the initial vector x0=[10]\xvec_0 = \twovec{1}{0}.

  2. Explain why this is happening and provide a contrast with how the power method usually works.

  3. How can we modify the power method to give the dominant eigenvalue in this case?

Austin, Understanding Linear Algebra, §5.2 Finding eigenvectors numerically, Exercise 5

AI Tutor

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