Re: Plot of (2 x^2 - x^3)^(1/3)

*To*: mathgroup at smc.vnet.net*Subject*: [mg112082] Re: Plot of (2 x^2 - x^3)^(1/3)*From*: Matthias Bode <lvsaba at hotmail.com>*Date*: Sun, 29 Aug 2010 02:51:05 -0400 (EDT)

Please check Table[{x, 2*x^2 - x^3, (2*x^2 - x^3)^ (1/3), Re[(2*x^2 - x^3)^(1/3)]}, {x, -4, 4}] Best regards, MATTHIAS BODE S 17.35775=B0, W 066.14577=B0 > Date: Sat, 28 Aug 2010 07:01:34 -0400 > From: bernard.vuilleumier at edu.ge.ch > Subject: [mg112057] Plot of (2 x^2 - x^3)^(1/3) > To: mathgroup at smc.vnet.net > > I see in Calcul Diff==E9rentiel et int==E9gral, N. Piskounov, Editions > MIR, Moscou 1970, on p. 210 the graph of (2 x^2 - x^3)^(1/3) with > negative values for x > 2, something like : > > Plot[Piecewise[{{(2 x^2 - x^3)^(1/3), x <== 2}, {-Re[(2 x^2 - > x^3)^(1/3)], x > 2}}], {x, -1, 3}] > > When I plot this function with : > > Plot[(2 x^2 - x^3)^(1/3) // Re, {x, -1, 3}] > > I obtain positives values for x > 3. I don't understand why. > Thank you very much for your help !