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MathGroup Archive 2007

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Re: pursuit curve (differential equations)

  • To: mathgroup at smc.vnet.net
  • Subject: [mg72874] Re: pursuit curve (differential equations)
  • From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
  • Date: Tue, 23 Jan 2007 05:30:28 -0500 (EST)
  • Organization: The Open University, Milton Keynes, UK
  • References: <ep1sq1$g13$1@smc.vnet.net>

Trijezni Pijanac wrote:
> hi i am doing pursuit curve in mathematica.. for instance, fox is chasing a
> rabbit - rabbit has a certain defined path (for example - a circle
> {cos(t),sin(t)}. fox always heads directly toward the rabbit. 
> 
> k - relative speed fox/rabbit
> p,q - rabbit's path (for instance a circle {cos(t),sin(t)}
> x,y - fox's path
> t - time :)
> 
> soln = NDSolve[
>       {
>         x'[t] == k.Sqrt[p'[t]^2 + q'[t]^2].(p - x[t])
> 		/Sqrt[(p - x[t])^2 + (q - y[t])^2],
>         y'[t] == k.Sqrt[p'[t]^2 + q'[t]^2].(y - q[t])
----------------------------------------------^
Missing variable: must be written y[t]

> 		/Sqrt[(p - x[t])^2 + (q - y[t])^2],
>         x[0] == poc0[[1]],
>         y[0] == poc0[[2]]
------------------^^^^^^^^^
What are the numerical values for the 1 by 2 vector poc0?

>         },
>       {x[t], y[t]}, {t, t0, t1}];
--------------------------^^--^^
What are the numerical values for t0 and t1?
> 
> but this wont work, any suggestions?
> 

Regards,
Jean-Marc


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