Math Problem Statement

Determine the type of critical point and its stability for the system given by: \( \begin{pmatrix} x' \\ y' \end{pmatrix} = \begin{pmatrix} 0 & 1 \\ -3 & -2 \end{pmatrix} \begin{pmatrix} x \\ y \end{pmatrix} \).

Solution

The question provided is as follows:

Q2:

  1. (a) Determine the type of critical point and its stability.
  2. (b) Find the critical point for the system given by:

(xy)=(0132)(xy).\begin{pmatrix} x' \\ y' \end{pmatrix} = \begin{pmatrix} 0 & 1 \\ -3 & -2 \end{pmatrix} \begin{pmatrix} x \\ y \end{pmatrix}.

Solution Outline

Let's address each part step-by-step.

Part (a): Determine the Type and Stability of the Critical Point

  1. Identify the critical point: For linear systems of the form x=Ax\mathbf{x}' = A \mathbf{x}, the origin (0,0)(0, 0) is typically a critical point.

  2. Find the Eigenvalues of the Matrix: To classify the critical point and determine stability, we need to find the eigenvalues of the matrix A=(0132).A = \begin{pmatrix} 0 & 1 \\ -3 & -2 \end{pmatrix}.

    The eigenvalues λ\lambda are found by solving the characteristic polynomial: det(AλI)=0.\det(A - \lambda I) = 0. This becomes: det(λ132λ)=0.\det \begin{pmatrix} -\lambda & 1 \\ -3 & -2 - \lambda \end{pmatrix} = 0.

    Expanding the determinant: (λ)(2λ)(1)(3)=λ2+2λ+3=0.(-\lambda)(-2 - \lambda) - (1)(-3) = \lambda^2 + 2\lambda + 3 = 0.

    Solving this quadratic equation: λ=2±4432=2±82=1±i2.\lambda = \frac{-2 \pm \sqrt{4 - 4 \cdot 3}}{2} = \frac{-2 \pm \sqrt{-8}}{2} = -1 \pm i\sqrt{2}.

  3. Classify the Eigenvalues: Since the eigenvalues are complex, λ=1±i2\lambda = -1 \pm i\sqrt{2}, they indicate a spiral type of critical point. The negative real part 1-1 means that the system is asymptotically stable (the origin is an attracting spiral).

Part (b): Find the Critical Point

Since this is a linear homogeneous system, the only critical point is at the origin, (0,0)(0, 0).

Summary

  1. Type of Critical Point: Spiral (because of complex eigenvalues).
  2. Stability: Asymptotically stable (because the real part of the eigenvalues is negative).

Would you like further explanation on any step, or details on eigenvalue calculation?


Here are some related questions:

  1. What does it mean for a system to be asymptotically stable?
  2. How do complex eigenvalues affect the behavior of a dynamical system?
  3. What types of critical points exist in dynamical systems?
  4. How do we determine stability for non-linear systems?
  5. What is the role of the Jacobian matrix in stability analysis?

Tip: Complex eigenvalues with a negative real part indicate an attracting spiral, which means trajectories will spiral towards the critical point.

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Math Problem Analysis

Mathematical Concepts

Differential Equations
Eigenvalues
Stability Analysis

Formulas

Eigenvalue formula: \( \det(A - \lambda I) = 0 \)
Characteristic polynomial of matrix \( A \)

Theorems

Stability Theorem for Linear Systems
Eigenvalue Classification for Stability

Suitable Grade Level

Undergraduate (Math/Engineering)