Real/Comlex function problem with D
- To: mathgroup at smc.vnet.net
- Subject: [mg74212] Real/Comlex function problem with D
- From: bar at ANTYSPAM.ap.krakow.pl
- Date: Wed, 14 Mar 2007 03:55:01 -0500 (EST)
Hi, I have a complex function F[x] When i defined: ff[x_]:=Arg[F[x]] (* i tried ComplexExpand[Arg[F[x]]] too *) I obtainned good Plot[ff[x]] - its real - (no complex) When i try ff1[x_]:=D[ff[x],x]; I found ff1 is Complex funtion again !! Why ? (i tried Evaluate; Element[x,Reals]; FullSimplify - always the same) Regards, Olaf