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Re: Re: SetDelayed::write ... [x_] is protected

  • To: mathgroup at smc.vnet.net
  • Subject: [mg97963] Re: [mg97899] Re: [mg97863] SetDelayed::write ... [x_] is protected
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Thu, 26 Mar 2009 05:25:36 -0500 (EST)
  • Reply-to: hanlonr at cox.net

Use the expression that I sent, i.e., use Set ( = ) rather than SetDelayed ( := ).


Bob Hanlon

---- Serych Jakub <Serych at panska.cz> wrote: 

=============
Thanks for the Flatten, now it seem that it works (without any error
messages), but in fact it doesn't work.

sol = {{i1 -> 220/x}, {i2 -> 100 + x}};
myfun[x_] := 50*i1 + 2*i2 /. Flatten[sol]
(no errors here) but:

In: myfun[1]

Out: 11000/x + 2 (100 + x)

and not 11202 which would be result for argument 1.

So it cannot recognize (or connect together with the pattern x_) the =
variable
x in the result from sol.

What to do with it?

Thanks

Jakub 


> -----Original Message-----
> From: Bob Hanlon [mailto:hanlonr at cox.net]
> Sent: Tuesday, March 24, 2009 12:46 PM
> To: Serych Jakub
> Cc: mathgroup at smc.vnet.net
> Subject: RE: [mg97863] SetDelayed::write ... [x_] is protected
>
> sol = {{i1 -> 220/x}, {i2 -> 100 + x}};
>
> myfun[x_] = 50*i1 + 2*i2 /. Flatten[sol]
>
> 2*(x + 100) + 11000/x
>
>
>
> Bob Hanlon
>
>
> On Tue, Mar 24, 2009 at 7:46 AM , Serych Jakub wrote:
>
> > Dear M users,
> > I have solution of equations which is dependend on one
> parameter lets
> > say:
> > sol={{i1->220/x}, {i2 -> 100+x}} and I need to define
> function based
> > on this solution with the x as argument lets say:
> myfun[x_]:=50*220/x
> > + 2 (100+x);
> >
> > I'm trying to do it like this:
> >
> > myfun[x_]:=50 * i1 + 2 * i2 /. sol
> >
> > But it prints the error message: "SetDelayed::write ... [x_] is
> > protected".
> >
> > Does anybody know what's the problem and how to define such
> function?
> >
> > Thanks in advance
> >
> > Jakub
>


--

Bob Hanlon



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