Operations on InterpolatingFunction

*To*: mathgroup at smc.vnet.net*Subject*: [mg100744] Operations on InterpolatingFunction*From*: Porscha Louise McRobbie <pmcrobbi at umich.edu>*Date*: Fri, 12 Jun 2009 05:46:12 -0400 (EDT)

Hi, Solving a simple differential equation: ifun = First[ u /. NDSolve[{u''[t] + u[t] == 0, u[0] == 0, u'[0] == 1}, u, {t, 0, \[Pi]}]] returns the InterpolationFunction object, as expected. I can integrate this function (and obtain another InterpolatingFunction to be plotted, etc.) by: Integrate[ifun[t], t] 1. Why doesn't the following produce an InterpolatingFunction in the same way? Integrate[ifun[t]^2, t] 2. How can I normalize the solutions found using NDSolve? Norm[ifunt[t]] doesn't work... Thanks for any help.