       Re: Simplifying constants...bug?

• To: mathgroup at smc.vnet.net
• Subject: [mg18559] Re: [mg18489] Simplifying constants...bug?
• From: calvitti at boes.ces.cwru.edu
• Date: Sat, 10 Jul 1999 02:18:50 -0400
• Organization: Case Western Reserve University
• References: <7m3l22\$shp@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```here's some intersting behavior in 3.0:

(a + c*d)/(b + c*d) //. c*d -> -z

gives (as expected):

(a - z)/(b - z)

yet

(a + c*d)/(c*d) //. c*d -> -z

no longer simplifes the denominator:

(a+b-z)/(c*d)

anyone know why?

+------------------------------------------+
alan c
systems and control engineering
case western reserve university

calvitti at alpha.ces.cwru.edu
+------------------------------------------+

"Ersek, Ted R" <ErsekTR at navair.navy.mil> writes:

> Morten G. Dyndgaard wrote:
> -----------------------------
> I am working with some annoyingly long equations that I want to simplify
> by including one set of parameters in a constant (or function) A, and
> another in B and so on.
>
> You can easily do:
> A = b+c+d+e
>
> but what I want to do is the reverse:
> b+c+d+e = A
> -----------------------------
>
> This should help.
> In:=
> expr=a+b+b1+c+c1+d+d1+e;
>
>
> In:=
> expr/.a+b+c+d+e->A
>
> Out=
> A+b1+c1+d1
>
>
> Regards,
> Ted Ersek

```

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