Re: Using InterpolatingFunction in Argument of NIntegrate

*To*: mathgroup at smc.vnet.net*Subject*: [mg57802] Re: Using InterpolatingFunction in Argument of NIntegrate*From*: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>*Date*: Thu, 9 Jun 2005 05:17:35 -0400 (EDT)*Organization*: Uni Leipzig*References*: <d8691p$c70$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi, f[t_?NumericQ] = x[t] /. NDSolve[ {x''[t] + x[t] == 0, x[0] == 0, x'[0] == 1}, x[t], {t, 0, 2Pi}][[1]] Plot[f[t], {t, 0, 2Pi}] NIntegrate[f[t], {t, 0, Pi}] ?? Regards Jens "Iggy" <blah at blah.com> schrieb im Newsbeitrag news:d8691p$c70$1 at smc.vnet.net... > Hi, > > I am solving numberically an ODE and outputing > the results into a function > f(x). This f(x) is some InterpolatingFunction. > > I would like to then use f(x) in a call to > NIntegrate in a way such as: > > NIntegrate[g(f(x),{x,0,1}] > > However I get an integrand not numerical error. > I can easily Plot g(f(x)) > and if I replace f(x) with some function like > x^2 everything works too. > > How can I get around this? > > Thanks, > > Iggy >