Re: pursuit curve (differential equations)

*To*: mathgroup at smc.vnet.net*Subject*: [mg72867] Re: pursuit curve (differential equations)*From*: dh <dh at metrohm.ch>*Date*: Tue, 23 Jan 2007 04:59:16 -0500 (EST)*References*: <ep1sq1$g13$1@smc.vnet.net>

Hi Trijezni, you have syntax errors: "." should be "*" and is not necessery. Functions must be written with arguments. See below. Daniel > 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]) ^ ^ > /Sqrt[(p - x[t])^2 + (q - y[t])^2], ^ ^ > x[0] == poc0[[1]], > y[0] == poc0[[2]] > }, > {x[t], y[t]}, {t, t0, t1}]; > > but this wont work, any suggestions? >