Re: normalization and square roots

*To*: mathgroup at smc.vnet.net*Subject*: [mg65787] Re: [mg65739] normalization and square roots*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Mon, 17 Apr 2006 02:28:44 -0400 (EDT)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

You need patterns on the LHS of the definition for f[0,...] myrule=-om+(-1+Sqrt[oro])^2-oro; Clear[f]; f[0,om_,oro_]=1; f[x_,om_,oro_]:=1/(Sqrt[oro]-Sqrt[om(1+x)^3+ol+oro])/. ol->myrule f[0,a,b] 1 f[0,0.3,0.4] 1 Bob Hanlon > > From: wtplasar at ehu.es To: mathgroup at smc.vnet.net > Subject: [mg65787] [mg65739] normalization and square roots > > [This post has been delayed due to email problems - moderator] > > > > I have this function > > f[x_, om_, oro_] := 1/(Sqrt[oro] - Sqrt[om(1 + x)^3 + ol + oro]) /. > ol -> myrule > > and I want to define a rule (myrule) so that > > f[0,om,or0]=1 > > If I set > > myrule=-om + (-1 + Sqrt[oro])^2 - oro; > > then it works find when I do not give numerical values to om and oro. > > For instance, if I evaluate f[0,a,b] I get 1, but if I evaluate > f[0,0.3,0.4] I get 3.77485. I think it is just because it is not taking > the right which is convenient for me. > > Can you help me? > > Thanks, > > Ruth > >