Re: Calculations with Interpolating Functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg88530] Re: Calculations with Interpolating Functions*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Wed, 7 May 2008 07:10:26 -0400 (EDT)*Organization*: Uni Leipzig*References*: <fvpcqn$mhn$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de

Hi, and add your functions to the list of differential equations, i.e., Join[yourODES, {ix2'[t]==x[t]^2, ix2[0]==0,isx'[t]==Sin[x[t]], isx[0]=== 0}] does not help ? Regards Jens Jo=E3o Paulo Casquilho wrote: > Hi > > > > I obtain an Interpolating function as a solution of a differential equa= tion > with the command NDSolve, lets call it =93solution=94, which gives = x(t). Next I > want to use this solution for further calculations. With the commands > =93result=Evaluate[x(t)/. First[solution]]=94 or =93result= = x(t)/.solution, > {t,0,tmax}=94 I do the plot x(t) without any problems. Now, with vers= ion 5.2 I > manage to integrate x(t) or linear functions of it. But when I try to > integrate non linear functions of x(t), like x(t)^2 or Sin[x(t)] (which= is > what I want), Mathematica is unable to give a numerical result, all I = get > is an integral saying that there is an InterpolatingFunction in the > integrand. With Mathematica 6 the linear integration does not work eith= er. > > Any help would be appreciated. > > > > Best Regards > > > > Joao Paulo > > >