Re: RE: A 3D Plot Query
- To: mathgroup at smc.vnet.net
- Subject: [mg94297] Re: [mg94261] RE: [mg94222] A 3D Plot Query
- From: Murray Eisenberg <murray at math.umass.edu>
- Date: Wed, 10 Dec 2008 04:44:19 -0500 (EST)
- Organization: Mathematics & Statistics, Univ. of Mass./Amherst
- References: <31362096.1228736527369.JavaMail.root@m02> <200812091159.GAA20944@smc.vnet.net>
- Reply-to: murray at math.umass.edu
Another "for engineers and scientists" version of a graph -- and not
what the poster requested. As I understand the query, what is desired
is the positive semi-axes shown emanating from the origin, with z up, x
forward, and y to the right (roughly). No frame.
David Park wrote:
> Sid,
>
> Not silly at all.
>
> Use cylindrical coordinates and ParametricPlot3D to get a surface with a
> circular base.
>
> Use the ViewPoint option to get the x and y axes in the position you want.
>
> With[{a = 5},
> ParametricPlot3D[{r Cos[\[Theta]], r Sin[\[Theta]],
> 2 - r^2}, {\[Theta], 0, 2 \[Pi]}, {r, 0, a},
> PlotPoints -> {30, 10},
> MaxRecursion -> 3,
> AxesLabel -> {"x", "y", "z"},
> ViewPoint -> {5, 5, 3},
> BoxRatios -> {1, 1, 1}]
> ]
>
>
> David Park
> djmpark at comcast.net
> http://home.comcast.net/~djmpark/
>
>
> From: pcoords29 at gmail.com [mailto:pcoords29 at gmail.com]
>
>
> Hi,
>
> This may sound silly, but I can't get it to work. (I'm using v 6.0)
>
> How do I get my 3D plots look as given in textbooks, ie. with the y-
> axis pointing to the right, the z-axis up and x-axis pointing out of
> the paper/screen ( showing the first octant)? I mean the kind of
> plots one draws on paper when working out surface integrals in
> Calculus classes.
>
> If this is of any help, I'd like to get the plot of the paraboloid
>
> z = 2-(x^2+y^2), as given in Fig. 10-10 of Spiegel's Advanced
> Calculus, Schaum Series.
>
> I tried
>
> Plot3D[2 - (x^2 + y^2), {x, -a, a}, {y, -a, a}],
>
> with various values of a. Unfortunately, none of them look like the
> traditional cap-shaped paraboloid.
>
> Thanks for any help.
>
> Sid.
>
>
>
>
>
>
--
Murray Eisenberg murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower phone 413 549-1020 (H)
University of Massachusetts 413 545-2859 (W)
710 North Pleasant Street fax 413 545-1801
Amherst, MA 01003-9305
- References:
- RE: A 3D Plot Query
- From: "David Park" <djmpark@comcast.net>
- RE: A 3D Plot Query