Forcing Re[]'s to be Real

*To*: mathgroup at smc.vnet.net*Subject*: [mg18223] Forcing Re[]'s to be Real*From*: afoglia at hal.physics.ucsb.edu (Anthony Foglia)*Date*: Tue, 22 Jun 1999 20:41:15 -0400*Organization*: University of California, Santa Barbara*Sender*: owner-wri-mathgroup at wolfram.com

I seem to have found an interesting problem involving computing the real part of complex numbers. (Interesting, in that it wasn't there a few weeks ago when I ran the (as-far-as-i-can-remember) exact same code.) I have a complex function: k[w] := Sqrt[w^2 (1 + (2 / (1 + I w)))] I want to graph the real and imaginary parts, but Mathematica doesn't want to express the Re[k[w]] as a real number. What do I mean? Well, if I type: Re[Sqrt[1+I]] I get out Re[Sqrt[1+I]] Same if I do Re[ComplexExpand[Sqrt[1+I]]], or Re[(1+I)^(1/2)]. But if I enter: Re[ComplexExpand[(1+I)^(1/2)] Mathematica is kind enough to respond with: 2^(1/4) Cos[Pi/8] I'm certain that this is the root of my problem, but I'll be damned if I know why Mathematica doesn't like it now, but did a few weeks ago. Any help? --Anthony

**Follow-Ups**:**Re: Forcing Re[]'s to be Real***From:*Daniel Lichtblau <danl@wolfram.com>