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Re: Differencing two equations
Posted:
Feb 11, 2013 4:37 AM


On 2/10/13 at 3:24 AM, g.c.b.at.home@gmail.com wrote:
>I'm trying to figure out how to difference two equations. Basically >if I have: a==r >b==s
>I'd like to get: ab == rs
>What I'm getting is more like (a==r)  (b==s). I'm not sure how >that's a useful result, but is there a function to do what I'm >looking for?
>A quick search of the archives seem to bring up ways of doing this >from using transformation rules to swap heads to unlocking the >Equals operator and hacking its behavior. I'd like to avoid doing >that kind of rewiring for a simple operation, and I'd like to keep >the syntax clean.
Here is one way, but it may not meet your criteria for clean syntax
In[1]:= eq1 = a == r; eq2 = b == s;
In[3]:= Equal @@ (Subtract @@ List @@@ {eq1, eq2})
Out[3]= ab==rs



