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Re: Re: Hold and Equal

• To: mathgroup at smc.vnet.net
• Subject: [mg73769] Re: [mg73734] Re: Hold and Equal
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Wed, 28 Feb 2007 04:28:03 -0500 (EST)
• Organization: Mathematics & Statistics, Univ. of Mass./Amherst
• References: <erufqm$s7j$1@smc.vnet.net> <200702271041.FAA23729@smc.vnet.net>
• Reply-to: murray at math.umass.edu

Unfortunately, such a ToString expression does not produce properly 
formatted mathematical text, where the powers are shown as actual 
superscripts.

dh wrote:
> Hi Murray,
> 
> a quick and dirty solution that does not create evaluation problems is 
> 
> to convert your expression into a string and make the replacement there:
> 
> fun[x_]:= StringReplace[ToString[x], "==" -> "="]
> 
> if you now say: fun[(a + b)^2 == Expand[(a + b)^2]] you get:
> 
>         2     2            2
> 
> (a + b)  = a  + 2 a b + b
> 
> 
> 
> Daniel
> 
> 
> 
> Murray Eisenberg wrote:
> 
>> 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 traditional 
> 
>> 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

• References:
  • Re: Hold and Equal
    • From: dh <dh@metrohm.ch>