Re: Solving differential equations with parameters

*To*: mathgroup at smc.vnet.net*Subject*: [mg79835] Re: Solving differential equations with parameters*From*: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>*Date*: Mon, 6 Aug 2007 03:38:09 -0400 (EDT)*Organization*: The Open University, Milton Keynes, UK*References*: <f91j5e$677$1@smc.vnet.net> <f9445k$mdg$1@smc.vnet.net>

Ivan wrote: > On Aug 4, 12:07 pm, Ivan <darkna... at gmail.com> wrote: >> Hi, I am trying to solve the differential equations like >> >> y'[x]= - Sin[ p*x + y[x] ] >> >> where p is a parameter. Now I want to solve the equation with respect >> to x for a range of values of p, instead for just a single p. >> What is the best way to do it? > > I now have a way to do it but there is another problem.. > > I use the Table command (I change the function for the sake of > demonstration) > > sol = NDSolve[{y'[x]==1/2y[x],y[0.01]==0.1}, y, {x, 0.01,1}]; > > g=Table[ {y[i*0.01]/.sol}, {i,100} ]; > > ListPlot[g]; > > The error message is gptn: Coordindate .. in ... is not a floating- > point number. > > The problem seems to be that y[x]/.sol generate not a "normal" number, > instead, the number is is a brace {...}. > > Can anyone help me? Use y[x]/.sol[[1]] or y[x]/.First[sol] Regards, Jean-Marc