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Re: NEWBIE: How do I use the results of a Solve?

• To: mathgroup at smc.vnet.net
• Subject: [mg95989] Re: [mg95963] NEWBIE: How do I use the results of a Solve?
• From: "Jaccard Florian" <Florian.Jaccard at he-arc.ch>
• Date: Sat, 31 Jan 2009 06:43:39 -0500 (EST)
• References: <200901310611.BAA28347@smc.vnet.net>

Like this :

Solve[2*x + 9 == 33, x] /. Rule -> Set

But it's not a good idea, because you will have to delete x later on, 
writing Clear[x]...

I would suggest to use Rules like this :

y == x*5 /. Solve[2*x + 9 == 33, x][[1]]

and so no variable will be fixed with a value!

Regards

Jaccard Florian



Rendez-vous le 21 mars 2009, lors de nos portes ouvertes.


-----Message d'origine-----
De : Tim Heger [mailto:timheger at yahoo.com]
Envoy=E9 : samedi, 31. janvier 2009 07:12
=C0 : mathgroup at smc.vnet.net
Objet : [mg95963] NEWBIE: How do I use the results of a Solve?

I can't figure out how to use the results of Solve I just created  as a new
variable.

Here's a simple example of what I am trying to do:

Solve[some equation, x]

Results in {x->12}

I then want to use the x in  y =  x * 5 for example....

Obviously when I try to use this it fails because Mathematica sees the
equation as y = {x->12} * 5  and not y = 12 *5 ...

How do I change the results from the Solve from a rule to an actual value I
can then use?

Thanks,

Tim

• References:
  • NEWBIE: How do I use the results of a Solve?
    • From: Tim Heger <timheger@yahoo.com>