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Predator-prey MATLAB phase portaits

  1. May 7, 2009 #1
    Hi all.

    I have a project for Diff Eq where I am to write code that when the user enters a value between 0 and 1 shifts a phase portrait between two given predator-prey functions. They are in the form:

    dy/dt = x( a - bx - cy)
    dx/dt = y(d - ey - fx)

    I have no clue how to go about this as they've never really taught us MATLAB but given us a crappy book on it :-/. I'm thinking eigen methods would be a good way to attack this. However when looking at the values I do not see how the associated eigenvalues and eigenvectors can be related to one another.

    I also thought I could enter the given constants a-f and try to have it so as the 0 < z < 1 value will cause a preset shift in the pictures. Sort of like a slider bar.
  2. jcsd
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