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Re: Problem with DSolve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg96495] Re: Problem with DSolve
  • From: dh <dh at metrohm.com>
  • Date: Sat, 14 Feb 2009 03:14:24 -0500 (EST)
  • References: <gn3bnf$pt9$1@smc.vnet.net>


Hi Tony,

solve first the general problem:

sol = y[x] /. DSolve[{y'[x] == .02*y[x] - y[x]^2}, y[x], x][[1]]

then determine the constant C[1]:

Solve[(sol /. x -> 0) == a, C[1]]

hope this helps, Daniel



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. >>

> 




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