Solving System of Differential Equations: Eigenvalues and Eigenvectors

Published on May 29, 2025

Linear-Algebra

Find the general solution to a system of differential equations X' = AX, given the eigenvalues and eigenvectors of the matrix A. The solution involves finding linearly independent solutions based on the eigenvalues and eigenvectors, including complex conjugate pairs.

Question

Answer

The problem asks us to find the solutions to the system of differential equations , given the eigenvalues and eigenvectors of the real matrix .
The given eigenvalues and eigenvectors are:
  1. Eigenvalue with eigenvector .
  2. Eigenvalue with eigenvector .
  3. Eigenvalue with eigenvector .
For a system of linear differential equations , if is an eigenvalue and is its corresponding eigenvector, then is a solution.
For the real eigenvalue and eigenvector , a solution is:
For the complex conjugate eigenvalues and , and their corresponding eigenvectors and , we can find two real solutions.
Let’s consider the complex solution corresponding to and :
We can write .
And the eigenvector can be written as .
Let , where and .
Now, substitute these into :
The two real solutions are the real and imaginary parts of :
The general solution to the system is a linear combination of these linearly independent solutions:
The final answer is .