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Re: coding problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg60193] Re: [mg60176] coding problem
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Wed, 7 Sep 2005 04:03:51 -0400 (EDT)
  • Reply-to: hanlonr at cox.net
  • Sender: owner-wri-mathgroup at wolfram.com

soln=y[x]/.DSolve[{x*y''[x]+(1+x)*y'[x]==0},y[x],x][[1]]

C[2] + C[1]*ExpIntegralEi[-x]


y'[0] is not defined


Limit[D[soln,x],x->0]

C[1]*Infinity


Bob Hanlon

> 
> From: "Ming Hong" <zhongming at gmail.com>
To: mathgroup at smc.vnet.net
> Date: 2005/09/06 Tue AM 01:26:47 EDT
> Subject: [mg60193] [mg60176] coding problem
> 
> I am trying to solve the following equations:
> 
> xy''+(1+x)y'=0
> xy'(0)=-1/2
> y(Infinity)=0
> 
> Here is what I put into Mathematica:
> 
> Dsolve[{x*y''[x]+(1+x)*y'[x]==0,x*y'[0]==-1/2,y[Infinity]==0},y,x]
> 
> It didn't work and I can not figure out why.
> 
> Thanks for your help!
> 
> Ming
> 
> 


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