Re: NDsolve problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg110745] Re: NDsolve problem*From*: Narasimham <mathma18 at hotmail.com>*Date*: Sun, 4 Jul 2010 03:10:24 -0400 (EDT)*References*: <i0kif0$183$1@smc.vnet.net>

On Jul 2, 4:27 pm, "ntina... at libero.it" <ntina... at libero.it> wrote: > Hello, > I haven't been using Mathematica for some years and now I need to ask you= for > help with NDSolve. I'm using version 6.0. --- > Thank you in advance. > Regards, > Valentina Boundary Conditions for y and y' need to be given at x = 0 exactly. If nearby points are taken for defining BC, different constants would result in. In the following, the constant looks wavy, but note y axis plot values are in a narrow range, are reasonably constant. s=NDSolve[{y''[x]+(2/x) y'[x]+(1+(2*a/x)*E^(-b*x)) (y[x])==0,y[0.1]==1,y'[0.1]==-a},y,{x,0.1,60}] Plot[Evaluate[(x*y[x])^2+(((x-0.5 Pi)*y[x-0.5 Pi]))^2/.s[[1]]],{x, 10,60},PlotRange->All] Narasimham