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Re: Replace in Modules

  • To: mathgroup at smc.vnet.net
  • Subject: [mg81233] Re: [mg81187] Replace in Modules
  • From: DrMajorBob <drmajorbob at bigfoot.com>
  • Date: Mon, 17 Sep 2007 03:31:25 -0400 (EDT)
  • References: <958016.1189935557863.JavaMail.root@m35>
  • Reply-to: drmajorbob at bigfoot.com

Neither one of them works -- nor should they -- but this does:

f[x_?NumericQ] := Module[{a}, a /. FindRoot[x == a^2, {a, 1}]]
f[2]

1.41421

or this

f[x_?NumericQ] := Module[{a}, a /. Solve[x == a^2, {a}]]
f[2]

{-Sqrt[2], Sqrt[2]}

Bobby

On Sat, 15 Sep 2007 03:07:08 -0500, Joerg Schaber <schaber at molgen.mpg.de>  
wrote:

> Hi,
>
> why doesn't the following give me the square root?
>
> f[x_] := Module[{a, y},y = x;Return[FindRoot[y == a^2, {a, 1}] ]]
>
> f[z] /. {z -> 2}
>
> where as
>
> f[x_] := Module[{a},Return[FindRoot[x == a^2, {a, 1}]]]
>
> f[z] /. {z -> 2}
>
> works fine?
>
> best,
>
> joerg
>
>



-- 

DrMajorBob at bigfoot.com


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