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