http://mathforum.org/kb List of forum topics en http://mathforum.org/kb/thread.jspa?messageID=7973314&tstart=0#7973314
Many thanks for the answers. I have adapted some of them to my needs.

Cheers

Ed


On Jan 3, 2013, at 12:37]]> Jan 5, 2013 2:18:08 AM Jan 5, 2013 2:18:08 AM emammendes@gmail.com 0 http://mathforum.org/kb/thread.jspa?messageID=7973320&tstart=0#7973320 ]]> Jan 5, 2013 2:18:08 AM Jan 5, 2013 2:18:08 AM 1 http://mathforum.org/kb/thread.jspa?messageID=7973313&tstart=0#7973313
If you wish to get fancy with this, you can extract both the real and
imaginary parts at once:

]]> Jan 5, 2013 2:18:08 AM Jan 5, 2013 2:18:08 AM murrayeisenberg@gmail.com 0 http://mathforum.org/kb/thread.jspa?messageID=7973319&tstart=0#7973319 ]]> Jan 5, 2013 2:18:08 AM Jan 5, 2013 2:18:08 AM 3 http://mathforum.org/kb/thread.jspa?messageID=7973307&tstart=0#7973307 any variables that should be treated as complex rather than as real.]]> Jan 5, 2013 2:18:08 AM Jan 5, 2013 2:18:08 AM murrayeisenberg@gmail.com 0 http://mathforum.org/kb/thread.jspa?messageID=7973318&tstart=0#7973318 ]]> Jan 5, 2013 2:18:07 AM Jan 5, 2013 2:18:07 AM 5 http://mathforum.org/kb/thread.jspa?messageID=7973306&tstart=0#7973306 ("=882") in the numerator of your fraction, for purposes of
explanation]]> Jan 5, 2013 2:18:02 AM Jan 5, 2013 2:18:02 AM murray@math.umass.edu 0 http://mathforum.org/kb/thread.jspa?messageID=7973309&tstart=0#7973309
re = Re[ComplexExpand[expr, s]] //
Simplify[#, Element[z, Reals]] &;

im =]]> Jan 5, 2013 2:17:24 AM Jan 5, 2013 2:17:24 AM hanlonr357@gmail.com 0 http://mathforum.org/kb/thread.jspa?messageID=7973308&tstart=0#7973308
Module[{w, s, z},
s = 5 + 3 I;
z = 12 - 2 I;
(w = 882)/(s^2]]> Jan 5, 2013 2:17:24 AM Jan 5, 2013 2:17:24 AM mathgroup@stein.org 0 http://mathforum.org/kb/thread.jspa?messageID=7973302&tstart=0#7973302
Two problems:

(1) Mathematica does not know that s is a complex variable.

(2) The functions Re[ ] and Im[ ] work only]]> Jan 5, 2013 2:17:24 AM Jan 5, 2013 2:17:24 AM rm.tech@mac.com 0