Re: Plot3D error
- To: mathgroup at smc.vnet.net
- Subject: [mg7344] Re: [mg7322] Plot3D error
- From: Richard Finley <trfin at fiona.umsmed.edu>
- Date: Tue, 27 May 1997 22:27:28 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Karl,
The problem is that there are 3 different roots of your equation since it is
a cubic root, and some of the roots are imaginary. These obviously cannot be
plotted in real space. To get Mma to default to the real roots only you can
use:
<<Miscellaneous`RealOnly`
prior to plotting and it will work correctly.
RF
At 02:23 AM 5/23/97 -0400, you wrote:
>Hello everybody.
>
>Can anyone tell me what's wrong?
>
>Clear[x,y,z];
>Plot3D[(1+2 x+y^2)^(1/3),{x,-10,10},{y,-10,10}]
>
>gives me error: Plot3D::gval: Function value 0.4+0.7I at grid point ...is
>not real
>etc.
>And function is not completely plotted.
>Any suggestion would be appreciated.
>
>Karl Kevala
>
>