What is the solution of this? 2nd part

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Discussion Overview

The discussion revolves around solving a specific ordinary differential equation (ODE) of the form F''' + FF''/2 = 0, with given boundary conditions. Participants explore numerical methods for solving this equation, particularly focusing on the non-linear shooting method and alternatives.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • Clausius2 seeks a numerical solution for the ODE and expresses confusion about the non-linear shooting method.
  • Max questions the necessity of the non-linear shooting method and suggests considering the standard Runge-Kutta method instead.
  • Max mentions a belief that the equation cannot be completely integrated analytically and offers to share any relevant findings.
  • Max provides several links to resources for solving ODEs in Matlab and suggests rewriting the original ODE as a system of first-order equations.
  • Clausius2 expresses gratitude for the resources and indicates a delay in further exploration of the problem due to final exams.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method for solving the ODE, with differing opinions on the appropriateness of the non-linear shooting method versus other numerical techniques.

Contextual Notes

The discussion includes references to specific methods and resources for solving differential equations, but it does not resolve the complexities or assumptions involved in the proposed approaches.

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.
 
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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.
 
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 .
 
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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. :smile:
 

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