Solve a non linear differential equation systems with only boundary conditions

Hi everybody,

I am currently trying to solve a differential equation of the form :

function dy= myfun(r,y)

N=200e3;
g=1.6861;
dy=zeros(2,1);
dy(2)=y(1).*r.*(N*pi/60)^2;
dy(1)=(y(1)./(g.*y(2))).*y(1).*r.*(N*pi/60)^2;

end

Only , I know from my physical problem only what happened on the edge (at r2=10mm). I tried then to use bvp4c, but I have the feeling they would need anyway at least one initial condition.

      guess=[val1;val2];
      solinit=bvpinit(linspace(0,r2),40),guess)
      sol=bvp5c(@interdisc_space_compressible,@bc,solinit)

where val1=y1(0) et val2=y2(r2) However, I would like to set val1=y1(r2) and val2=y2(r2) instead!

Any hint??

Thanks!!!

Answer 1

[Bill Greene]

You have a system of two first order differential equations so you need just two boundary conditions. I would guess that specifying y1(r2) and y2(r2) is fine.

What kind of problem are you running into? If you post your complete example, we might be able to help.

Bill