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Re: Q

  • To: mathgroup at smc.vnet.net
  • Subject: [mg41405] Re: [mg41390] Q
  • From: Selwyn Hollis <selwynh at earthlink.net>
  • Date: Sun, 18 May 2003 05:02:43 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Though there's probably a Mathematica-ally slicker way, the following 
will work (and I beg forgiveness for the Do loop!):

n=4;
derivs = Join[{f[t]},
    Table[D[F[f[t]],{t,k}], {k,0,n}]]//. {t->0, f[0]->f0};

Do[fk = D[f[t], {t,k}]/. t->0;
     derivs = derivs /. fk->derivs[[k+1]], {k,1,n}];
derivs

[reference/plug: A Mathematica Companion for Differential Equations, by 
me.]
-----
Selwyn Hollis
http://www.math.armstrong.edu/faculty/hollis


On Saturday, May 17, 2003, at 05:50  AM, Stepan Yakovenko wrote:

> HI!
>
>   I've got an equation f'[t]=F[f[t]].
>   F[] is known and analytic, (say
>   F[x]=x*x). I know f[0]=f0. f0 is
>   a number. I want to get all f'[0],
>   f''[0], f'''[0], ...  assigned
>   to their numberical values that can be
>   unambiguously found after differentiating
>   the source equation as many times as
>   needed.
>
>
> -- 
> Try "win /t" to run Windows in text mode
>
>
>



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