Re: Simplify further

*To*: mathgroup at smc.vnet.net*Subject*: [mg61809] Re: [mg61791] Simplify further*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Mon, 31 Oct 2005 01:17:04 -0500 (EST)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

FullSimplify eliminates the Sqrt $Version 5.2 for Mac OS X (June 20, 2005) f[x_] := c/(x - p) + Conjugate[c]/(x - Conjugate[p]) soln=Simplify[Solve[D[f[x],x]==0,x]]; FullSimplify[f[x]/.soln] {(Re[c]^2*Sign[c])/(Im[c]*Im[p]*Sign[c] - c*Im[p]*Sign[Im[p]]), Re[c]^2/(Im[p]*(Im[c] + Conjugate[c]*Sign[c]* Sign[Im[p]]))} Bob Hanlon > > From: "Thomas Schmelzer" <thomas.??? at balliol.ox.ac.uk> To: mathgroup at smc.vnet.net > Date: 2005/10/30 Sun AM 12:43:20 EDT > Subject: [mg61809] [mg61791] Simplify further > > Hi experts, > > Let > > f[x_] := c/(x - p) + c\[Conjugate]/(x - p\[Conjugate]) > > I am interested in local extrema > > Solve[D[f[x], x] == 0, x] > > Mathematica gives me a list. > > I plug those values into f again. > > Using the Simplify command I get expression as > > sqrt(- c conjugate c ( p - conjugate p ) ^2 ) > > Is there a way that Mathematica simplifies that to > > 4*(abs (c))^2 (Im p)^2 > > cheers > > Thomas > > > > >