Re: Unexpected Output When Plotting...

*To*: mathgroup at smc.vnet.net*Subject*: [mg125495] Re: Unexpected Output When Plotting...*From*: Bill Rowe <readnews at sbcglobal.net>*Date*: Thu, 15 Mar 2012 00:35:30 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

On 3/14/12 at 12:40 AM, jwkochanski at mymail.vcu.edu (James Kochanski) wrote: >Can anyone explain to me why Graphs #5 and #6 (please see below) do >not include any output for x < 0 and x < -1, respectively? >Following graph is only plotted from x = 0 to x = 10 Graph #5 >: Plot[Cos[(x^3)^(1/3)], {x, -10, 10}] >Following graph is only plotted from x = -1 to x = 10 Graph #6 >: Plot[Cos[(x^3 + 1)^(1/3)], {x, -10, 10}] By default, Mathematica assumes all variables are complex variables. When taking a cube root of a negative value, Mathematica does not by default return real values. Instead, Mathematica returns a complex value by default. And since Plot cannot plot a complex value, nothing is plotted in the regions you note above.