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Re: Hold and Equal

• To: mathgroup at smc.vnet.net
• Subject: [mg73809] [mg73809] Re: Hold and Equal
• From: "dimitris" <dimmechan at yahoo.com>
• Date: Fri, 2 Mar 2007 06:03:25 -0500 (EST)
• References: <erufqm$s7j$1@smc.vnet.net>

Hello again Murray.

Searching a little in the archives I found a thread which may be (???)
interesting for you!

http://groups.google.gr/group/comp.soft-sys.math.mathematica/browse_thread/=
thread/af1d5be49c035da7/39f11052231954e6?lnk=gst&q=&rnum=4&hl=el#39=
f11052231954e6


Regards
Dimitris


=CF/=C7 Murray Eisenberg =DD=E3=F1=E1=F8=E5:
> How can I produce in an Output cell (under program control) an
> expression like the following,
>
>    (a+b)^2 = a^2+ 2 a b + b^2
>
> where instead of the usual Equal (==) I get a Set (=), as in tradit=
ional
> math notation?  I want to input the unexpanded (a+b)^2 and have the
> expansion done automatically.
>
> Of course, I can try something like the following:
>
>    (a+b)^2 == Expand[(a+b)^2])
>
> So how do I convert the == to =?  Of course
>
>    ((a + b)^2 == Expand[(a + b)^2]) /. Equal -> Set
>
> gives a Set::write error.  And
>
>    (Hold[(a + b)^2 == Expand[(a + b)^2]]) /. Equal -> Set
>
> doesn't actually evaluate the Expand part and leaves the "Hold" wrapper.
>
>
>
>
> --
> Murray Eisenberg                     murray at math.umass.edu
> Mathematics & Statistics Dept.
> Lederle Graduate Research Tower      phone 413 549-1020 (H)
> University of Massachusetts                413 545-2859 (W)
> 710 North Pleasant Street            fax   413 545-1801
> Amherst, MA 01003-9305