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Re: disable canceling

  • To: mathgroup at smc.vnet.net
  • Subject: [mg106495] Re: [mg106465] disable canceling
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Thu, 14 Jan 2010 05:50:41 -0500 (EST)
  • Reply-to: hanlonr at cox.net

prod[x_, y_, sym_: s] := HoldForm[Evaluate[
      Numerator[x]*Numerator[y]]]/
    HoldForm[Evaluate[
      Denominator[x]*Denominator[y]]] /.
   (n_ + sym) :> (sym + n);

g[s_] = s (s + 1)/(s + 2);

c[s_] = 1/(s (s + 1));

l[s_] = prod[g[s], c[s], s];

l[s]

s (s+1)/s (s+1) (s+2)

l[s] // ReleaseHold

1/(s+2)


Bob Hanlon

---- Petr Martinec <petr.martinec at gmail.com> wrote: 

=============
Hi all,
is here posibility to prevent canceling in Mathematica? I need it to
work with transfer and contreller functions (dynamic system theory). I
would like to input like this

g[s] = s (s + 1)/((s + 1) (s + 2));

and after evaluation get same expression. Another situation is:

input:

g[s] = s (s + 1)/(s + 2);
c[s] =1/(s(s + 1));
l[s] = g[s] c[s]

output:
l[s] = s(s + 1)/(s(s + 1)(s + 2))

It is possible to get this result?

thanks for your answers.




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