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Can you please tell me how to plot $\sqrt{r}$ in 3d sph polar plot?

In the spherical plot 3d there is no option I can put variable r. So how should I proceed.

ricci1729
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  • So you want $\mathbb{R}^3\to \mathbb{R}$ function? In exactly this case maybe better just Plot[Sqrt[r],{r, 0, rmax}]. In more complicated example, http://mathematica.stackexchange.com/q/19575/5478 – Kuba Jan 24 '14 at 11:08
  • @Kuba yes. actually I have to draw $|\bar{x}|^\frac{1}{2}$ where $\bar{x}\in \mathbb{R}^3$ i.e $\bar{x}=(x,y,z)$. – ricci1729 Jan 24 '14 at 11:10
  • To plot $\sqrt{r}$ vs. $(x,y,z)$, you would need four coordinates. See for example these questions: 19575, 20023, 25277, 26636 - (Oh, Kuba beat to the first one while I was searching. :) – Michael E2 Jan 24 '14 at 11:19
  • @MichaelE2 About that link, shouldn't the title be corrected to "3D functions", I mean, th "n" in "n-D functions" usualy reffers to dimension of a domain, doesn't it? – Kuba Jan 24 '14 at 11:23
  • To MichaelE2 and Kuba Please correct me if I have mistakes. I need the plot in 3D. Please see this notes on sobolev space (pg 21, Fig 2.2)where I encountered this http://www.iecn.u-nancy.fr/~munnier/files/cours_edp.pdf I want to reproduce the plot and I got the problem. Thanking you both once again. – ricci1729 Jan 24 '14 at 11:27
  • @Kuba Yes, that would be correct, from a mathematician's point of view. Often others refer to the dimension of the embedding, e.g. a 3D curve meaning a 1D object in ${\Bbb R}^3$. The standard embedding of the graph of a real-valued function $(x, f(x))$ takes $n+1$ coordinates, if $x \in {\Bbb R}^n$. Calling it 4D actually helped me find the question, so I don't object to the loose use of the terminology. – Michael E2 Jan 24 '14 at 11:35
  • @ricci1729 The figure is for $u :{\Bbb R}^2 \rightarrow {\Bbb R}$, for which you can use RevolutionPlot3D. – Michael E2 Jan 24 '14 at 11:39
  • Just to make @MichaelE2 's suggestion explicit, you could do RevolutionPlot3D[Sqrt[r], {r, 0, 1}]. – b.gates.you.know.what Jan 24 '14 at 13:25

1 Answers1

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ParametricPlot3D[{u, v, Sqrt@Sqrt[ u u + v v]}, {u, -2, 2}, {v, -2, 2},
                RegionFunction -> (Norm[{#4, #5}] < 1 &), AspectRatio -> 1, 
                MeshFunctions -> {(#3 &), (ArcTan[#2, #1] &)}]

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Dr. belisarius
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