Results 1 to 3 of 3

Math Help - phase portrait for ODE

  1. #1
    Member
    Joined
    Apr 2006
    Posts
    91

    Question phase portrait for ODE

    iv been given an ode

    dx/dt = x^4 + 4*(x^3) - 60*(x^2)

    i want to sketch the phase porrait for this ODE...does any have any ideas or can show me how to what to do thankz
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Global Moderator

    Joined
    Nov 2005
    From
    New York City
    Posts
    10,616
    Thanks
    9
    Quote Originally Posted by dopi View Post
    iv been given an ode

    dx/dt = x^4 + 4*(x^3) - 60*(x^2)

    i want to sketch the phase porrait for this ODE...does any have any ideas or can show me how to what to do thankz
    The general solution is,
    \frac{1}{5}x^5+x^4-20x^3+C
    The curves are represented below.
    (There is more to the curves, it just happens to be far away).
    Attached Thumbnails Attached Thumbnails phase portrait for ODE-picture3.gif  
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Apr 2006
    Posts
    91

    Question asymptotic behaviour

    have the ode

    dx/dt = x^4 +4(x^3) - 60(x^2)

    generally the solution s x(t) satisfy x(0) = x[0]

    and i found out that the
    attactor is -10
    repellor is 6
    and 0 is niether

    however i want to describe the asymptotic behaviour of the solution satisfying x(0) = 1/2 , which is were i got stuck??
    Last edited by dopi; February 7th 2007 at 11:03 AM. Reason: dont need the other question
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Phase Lines
    Posted in the Differential Equations Forum
    Replies: 8
    Last Post: April 8th 2011, 05:21 AM
  2. Phase Space/ State Space/ Phase Portrait
    Posted in the Differential Equations Forum
    Replies: 1
    Last Post: October 12th 2010, 01:40 PM
  3. Phase Portrait using Isoclines?
    Posted in the Differential Equations Forum
    Replies: 1
    Last Post: March 23rd 2010, 01:43 PM
  4. phase shift
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: November 15th 2009, 07:58 PM
  5. Out of phase
    Posted in the Trigonometry Forum
    Replies: 4
    Last Post: November 30th 2007, 02:59 PM

Search Tags


/mathhelpforum @mathhelpforum