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Re: Adding equations

• To: mathgroup at smc.vnet.net
• Subject: [mg14401] Re: Adding equations
• From: dreissBLOOP at bloop.earthlink.net (David Reiss)
• Date: Sun, 18 Oct 1998 15:10:06 -0400
• Organization: EarthLink Network, Inc.
• References: <703u1n$hup@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

In article <703u1n$hup at smc.vnet.net>, Lawrence Walker
<lwalker701 at earthlink.net> wrote:

> Group:
> 
> I've been trying to add two equations as follows:
> 
> In[4]:=
>     a==b;
> In[5]:=
>     c==d;
> In[6]:=
>     %4+%5
> Out[6]=
>     (a==b)+(c==d)
> 
> The result I was looking for is (a+c)==(b+d). The following works but it
> seems clumsy. In[7]:=
>     %4[[1]]+%5[[1]]==%4[[2]]+%5[[2]] Out[7]=
>     a+c==b+d
> Is there a way to elegantly add (sub, mult, div) two equations?  Also is
> there an elegant way to add (sub, mult, div) an expression to both
> sides of an equation?
> 
> Lawrence Walker


MathSource has an item by Roman Maeder that does just this. See:

"Automatic Threading of Equations

Roman E. Maeder

Make listable functions thread over equations as they  do over lists.
Allows for easy manipulation of equations. "

This is at

http://www.mathsource.com/Content/Enhancements/Algebraic/0209-124


--David Reiss


*<>*  David Reiss   Editor-at-large for MathSource *<>*  Email:  
dreiss at NOSPAMearthlink.net

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