Cannot plot this functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg53830] Cannot plot this functions*From*: Milind Gupta <milind.gupta at gmail.com>*Date*: Sat, 29 Jan 2005 06:02:38 -0500 (EST)*Reply-to*: milind_gupta at ieee.org*Sender*: owner-wri-mathgroup at wolfram.com

Hello, I have a function of a phase response like: -ArcTan[1 - sqrt(2)* Im[Ï?] - Re[Ï?^2], -Im[Ï?^2] + sqrt(2)* Re[Ï?]] I need to plot the negative derivative of this function with respect to Ï?. Whne I use plot it gives me the error: function is not a machine - size real number at Ï? =1.8622242690864824`*^-7 How can I avoid this problem?? Milind