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What is the solution of this? 2nd part

  1. May 10, 2004 #1

    Clausius2

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    Hi Max,

    Thanks very much, but now I am puzzled solving this problem:

    F'''+FF''/2=0

    F'(-infinite)=1
    F(-infinite)=0
    F'(infinite)=0

    I am looking for a numerical solution, and I have been trying unsuccesfully to understand the non-linear shooting method, in order to code it with Matlab.

    Be a good man, Max, and help an ODE's world wanderer.
     
  2. jcsd
  3. May 10, 2004 #2
    hi

    Hi, Clausius2;

    > I am looking for a numerical solution, and I have been trying unsuccesfully
    > to understand the non-linear shooting method, in order to code it with
    > Matlab.

    Is it a goal to code it in Mathlab, or you just need to code it somewhere? And why non-linear shooting method? Why not standard RK4 (Runge-Kutta of the 4th order)?
    To say the truth, I don't know Mathlab at all. Sorry for the stupid suggestion, but have you tried to find a ready Mathlab program in the Internet for any DE (system of DEs)? Try here for example: http://www.math.umn.edu/~olver/matlab.html.
    Then, why not rewrite the original DE as three first-order DEs and solve that system? I did this, but it was 100 years ago and I programmed in QuickBasic.

    > Be a good man, Max, and help an ODE's world wanderer.

    I would like to, but I'm mostly interested in _analytic_ solutions. And this particular equation is _very_ interesting since they say it cannot be completely integrated analytically (http://mathworld.wolfram.com/BlasiusDifferentialEquation.html).
    If I find smth related to your problem, I'll post it here.

    Best of luck,
    Max.
     
  4. May 10, 2004 #3
    check this

    Clausius2,
    check this link for using Mathlab for solving of ODEs:
    http://math.rice.edu/~polking/odesoft/dfpp.html,
    and these ones for numerical solving of ODEs in general:
    http://mathlab.cit.cornell.edu/math_software_resources/math_software_resources.html,
    http://archives.math.utk.edu/software/msdos/diff.equations/.html.
    Best of luck,
    Max.

    P.S. Well, man. It seems to me that I found the description of integration of the problem similar to yours. Read
    Example: Using Continuation to Verify a Solution's Consistent Behavior
    right here: http://www.mathworks.com/access/helpdesk/help/techdoc/math_anal/diffeq22.html#709310.
    Input beta=0, 1/2 in front of y*y'' and change the BCs and that seems to be it.
    Check this link just in case: http://www.mathworks.com/access/helpdesk/help/techdoc/math_anal/math_anal_example_index.html.
     
    Last edited: May 10, 2004
  5. May 12, 2004 #4
  6. May 29, 2004 #5

    Clausius2

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    Thanks

    Thank you so much, Max.

    I'm sure your links will be very useful. Now I am with my final exams, so I will come back to this problem on July.

    What a pity you are not a woman, because I would ask you to marry with me. :rofl:
     
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