Re: Problem with DSolve

*To*: mathgroup at smc.vnet.net*Subject*: [mg96465] Re: Problem with DSolve*From*: Peter Breitfeld <phbrf at t-online.de>*Date*: Sat, 14 Feb 2009 03:08:54 -0500 (EST)*References*: <gn3bnf$pt9$1@smc.vnet.net>

Tony wrote: > can anyone help what is wrong? > On version 7 I enter > > DSolve[{y'[x]==.02*y[x]-y[x]^2,y[0]==a},y[x],x] > > and get > > During evaluation of In[58]:= Solve::ifun: Inverse functions are being > used by Solve, so some solutions may not be found; use Reduce for > complete solution information. >> > During evaluation of In[58]:= Solve::ifun: Inverse functions are being > used by Solve, so some solutions may not be found; use Reduce for > complete solution information. >> > During evaluation of In[58]:= DSolve::bvnul: For some branches of the > general solution, the given boundary conditions lead to an empty > solution. >> > If you avoid using Reals you will still get the warning Solve::ifun, but not {} as result DSolve[{y'[x] == 1/5*y[x] - y[x]^2, y[0] == a}, y[x], x] ^^^ During evaluation of In[29]:= Solve::ifun: Inverse functions are being used by Solve, so some solutions may not be found; use Reduce for complete solution information. >> Out[29]= {{y[x] -> (a E^(x/5))/(1 - 5 a + 5 a E^(x/5))}} GruÃ? Peter -- _________________________________________________________ Peter Breitfeld, Bad Saulgau --- http://www.pBreitfeld.de