Re: Plot of (2 x^2 - x^3)^(1/3)
- To: mathgroup at smc.vnet.net
- Subject: [mg112125] Re: Plot of (2 x^2 - x^3)^(1/3)
- From: Peter <insomnia.berlin at gmail.com>
- Date: Tue, 31 Aug 2010 04:27:04 -0400 (EDT)
- References: <i5aqbk$eru$1@smc.vnet.net>
On 28 Aug., 13:02, Bernard <bernard.vuilleum... at edu.ge.ch> wrote:
> 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 !
Hi Bernard,
maybe you want
Plot[Root[#^3-(2 x^2-x^3)&,1]//Re,{x,-1,4}]
?
Peter