Absolute value

*To*: mathgroup at smc.vnet.net*Subject*: [mg110596] Absolute value*From*: Marco Masi <marco.masi at ymail.com>*Date*: Sun, 27 Jun 2010 04:55:54 -0400 (EDT)

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.