MaplePrimes - answers and comments on Question, Change Sign of fraction

sort, numer, denom

Carl Love — Mon, 04 Mar 2013 05:45:48 Z

Assuming that ex is set to the expression that you want to manipulate, it can be done as

sort(-numer(-ex)/denom(ex), x);

The second argument to sort, the x, is to tell it which variable that you want to appear first.

two ways

acer — Mon, 04 Mar 2013 05:52:53 Z

Here are two approaches, the second of which gets that precise form.

(There are more ways to do this particular example, but from just this one stated example and no more description it is not possible to completely characterize some general task that you may or may not have in mind.)

Download denom.mw

acer

with dividend

Alejandro Jakubi — Mon, 04 Mar 2013 09:53:42 Z

I would rephrase acer's second approach by means of the procedure dividend:

T := -z/(x-z):
dividend(T,sign(denom(T),z),[u->u,u->sort(u,[z])]);
                                       z
                                     -----
                                     z - x

dividend(T,sign(denom(T),z),[u->u,u->sort(u,[z],':-descending')]);
                                       z
                                     -----
                                     z - x

Thank you guys! Sorry for the late response. I

maxwell_22 — Wed, 20 Mar 2013 19:26:05 Z

Thank you guys!

Sorry for the late response.

I used "acer´s" second way and it worked perfectly!

Best regards!