Re: Absolute value

*To*: mathgroup at smc.vnet.net*Subject*: [mg110617] Re: Absolute value*From*: DC <b.gatessucks at gmail.com>*Date*: Mon, 28 Jun 2010 02:30:07 -0400 (EDT)*References*: <i073n4$kk1$1@smc.vnet.net>

Try ComplexExpand as in : In[9]:= Simplify[ ComplexExpand[Abs[Exp[I phi1] + Exp[I*phi2]]]] // TrigReduce Out[9]= Sqrt[2] Sqrt[1 + Cos[phi1 - phi2]] -Francesco On 06/27/2010 09:56 AM, Marco Masi wrote: > I would like to calculate the absolute value of complex quantities. For example Abs[Exp[I phi1]+Exp[I*phi2]], which sould give 2 (1+cos(phi1-phi2)). However it does not work. I tried to use real numbers as assumtion, but it always answers "Abs[Exp[I phi1]+Exp[I*phi2]]". What am I doing wrong? > > Regards, Mark. >