- **Calculus & Beyond Homework**
(*http://www.physicsforums.com/forumdisplay.php?f=156*)

- - **Systems of Differential Equations- Two models of interacting species**
(*http://www.physicsforums.com/showthread.php?t=274952*)

Systems of Differential Equations- Two models of interacting species1. Given Information/ObjectivesThe following system for "stable competition": dx/dt=(2-2x-y)x dy/dt=(2-x-2y)y Find the equilibrium points for the system. Using the Jacobian matrix, linearize the system about the equilibrium that has both species present. Classify this equilibrium. Plot direction field and orbits. 2. The attempt at a solutionAfter finding equilibrium points (2/3,2/3), and the Jacobian (provided that the equilibrium points I found were correct) for the previously mentioned points (J[2/3,2/3]=28/9). I don't know where to go from here; how do I know what kind of equilibrium it is?? |

Re: Systems of Differential Equations- Two models of interacting speciesA few points:
1) There are 3 equilibrium (aka fixed) points; you have found one of them. 2) The Jacobian is a 2x2 matrix, with entries functions of x and y; evaluating it at a point is still a 2x2 matrix. 3) The Jacobian evaluated at a point allows you to classify the equilibrium point in the linearised system. For example, if it has two distinct positive eigenvalues, then the equilibrium point is an unstable proper node. The corresponding eigenvectors, one being dominant, allow you to sketch the direct field near the fixed point. I suggest you consult your notes or text to become aware of the other types. |

All times are GMT -5. The time now is 08:00 PM. |

Powered by vBulletin Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.

© 2014 Physics Forums