# [R] how to plot implicit functions

Fabrizio Berloco oquark2005 at libero.it
Fri Dec 26 17:23:21 CET 2008

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YIHSU CHEN-3 wrote:
>
> Dear R users --
>
> I think this question was asked before but there was no reply to it.
> I would appreciate any suggestion any of you might have.  I am
> interested in plotting several "implicit functions" (F(x,y,z)=0) on
> the same fig.     Is there anyone who has an example code of how to do
> this?
>
> Thank you
>
> Yihsu
>
> If almost one of the variables are explicitable, you can use maxima plot3d
> function in this form:
>
> plot3d([fx,fy,fz],[x,xmin.xmax],[y,ymin,ymax],['grid,50,15]);
>
> i.e:
>
> if you have this function:
> x=(z^2/(127*(y+0.325-3.4*10^(-3)*z+1.2*10^(-5)*z^2))), you'll be able to
> explicitly write x or y, but not z; in this case you won't be able to plot
> in the right way the 3dimensional plot with standard use of plot3d. In
> order to do it correctly, use the command above in that form, so that:
>
>
> plot3d([z^2/127*(y+0.325-3.4*10^(-3)*z+1.2*10^(-5)*(z^2)),y,z],[y,0,0.08],[z,0,400],['grid,50,15]);
>
> parametric3d() function of R is the same thing!
>
>
>
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