Testing Stability of Linear System Fixed Points

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Homework Help Overview

The discussion revolves around classifying the fixed points of a given linear system and determining their stability. The system is defined by the equations \(\dot{x}=x + y\) and \(\dot{y}=x + 3y\), with a focus on the fixed point at (0,0).

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the identification of the fixed point and question the validity of stating a fixed point exists at dy/dx = 0/0. There is also inquiry into methods for testing stability, including references to eigenvalues of the coefficient matrix.

Discussion Status

The discussion is ongoing, with participants seeking clarification on the concept of stability and the methods to test it. Some guidance has been offered regarding the use of eigenvalues, but no consensus has been reached on the classification of the fixed point.

Contextual Notes

There appears to be confusion regarding the interpretation of the fixed point and the mathematical implications of the expression dy/dx = 0/0. Participants are also navigating the constraints of their homework requirements.

coverband
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Homework Statement



Classify the fixed points of the following linear system and state whether they are stable or unstable

\dot{x}=x + y
\dot{y} = x + 3y

Homework Equations



The Attempt at a Solution


Fixed point at dy/dx = 0/0. Therefore fixed point = (0,0)

How does one test for stability?

Thanks
 
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coverband said:

Homework Statement



Classify the fixed points of the following linear system and state whether they are stable or unstable

\dot{x}=x + y
\dot{y} = x + 3y

Homework Equations



The Attempt at a Solution


Fixed point at dy/dx = 0/0. Therefore fixed point = (0,0)

How does one test for stability?

Thanks
0/0 is not a number, so how can you say that there is a fixed point at dy/dx = 0/0?
 


How does one test for stability?
 


coverband said:
How does one test for stability?

Doesn't your text have a test for stability which involves looking at the eigenvalues of the coefficient matrix on the right side?
 

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