[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
## Re: System of two equations of ODE2

**From**: |
Marco Atzeri |

**Subject**: |
Re: System of two equations of ODE2 |

**Date**: |
Wed, 24 Dec 2014 10:37:26 +0100 |

**User-agent**: |
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 |

On 12/24/2014 9:01 AM, ben wrote:

Hi!
Thanks for the answers.
The sistem is 2 ODE, whit four initial conditions.
I make this program but it doesn't work.
<http://octave.1599824.n4.nabble.com/file/n4667923/dsf.png>

1st rule, don't paste image.
It make difficult for us to reply.
the Equation in clearly of second grade as
acceleration=d(velocity)/dt=d2(space)/dt2=-Fgravity/mass

The vector of initial conditions i correct like that? o i have to do
x0=zeros(1,4);
X0(1)=G+h
x0(2)=0
X0(3)=0
x0(4)=vo
i don't know how tho make it.

as the four variables are
x,y,vx,vy
you can define f as
[dx/dt, dy/dt, d(vx)/dt,d(vy)/dt] =[ vx, vy, -Fx/mass, -Fy/mass]

And another problem i want to plot (x,y), the position vector but it draws
something estrange...
Thanks.

Regards
Marco