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

*To*: mathgroup at smc.vnet.net*Subject*: [mg112057] Plot of (2 x^2 - x^3)^(1/3)*From*: Bernard <bernard.vuilleumier at edu.ge.ch>*Date*: Sat, 28 Aug 2010 07:01:34 -0400 (EDT)

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 !