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Re: Adding equations

• To: mathgroup at smc.vnet.net
• Subject: [mg14386] Re: [mg14342] Adding equations
• From: Lawrence Walker <lwalker701 at earthlink.net>
• Date: Sun, 18 Oct 1998 15:09:53 -0400
• Organization: Morgan State University: COMSARE
• References: <005301bdf827$56efa1c0$59130318@cc638315-a.hwrd1.md.home.com>
• Sender: owner-wri-mathgroup at wolfram.com

Kevin,

This doesn't work for subtracting and dividing equations.

In[9]:=
Thread[eq[1]-eq[2],Equal]
Out[9]=
a-(c==d)==b-(c==d)
In[10]:=
Thread[eq[1]/eq[2],Equal]
Out[10]=
\!\(a\/\(c == d\) == b\/\(c == d\)\)

Lawrence Walker

"Kevin J. McCann" wrote:

> eq1 = a == b
> eq2 = c == d
>
> Thread[eq1 + eq2,Equal]
>
> a+c==b+d
>
> The "Equal" in the Thread is the key.
>
> Kevin
>
> -----Original Message-----
> From: Lawrence Walker <lwalker701 at earthlink.net>
To: mathgroup at smc.vnet.net
> To: mathgroup at smc.vnet.net <mathgroup at smc.vnet.net>
> Date: Thursday, October 15, 1998 5:18 AM
> Subject: [mg14386] [mg14342] Adding equations
>
> >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
> >
> >