Re: Re: A 3D Plot Query
- To: mathgroup at smc.vnet.net
- Subject: [mg94296] Re: [mg94256] Re: [mg94222] A 3D Plot Query
- From: Murray Eisenberg <murray at math.umass.edu>
- Date: Wed, 10 Dec 2008 04:44:08 -0500 (EST)
- Organization: Mathematics & Statistics, Univ. of Mass./Amherst
- References: <200812081122.GAA15850@smc.vnet.net> <200812091158.GAA20808@smc.vnet.net>
- Reply-to: murray at math.umass.edu
Neither produces what a mathematician might typically draw for students
(as contrasted with what might appear in a physics or engineering
publication).
Yes, the axes are there now, but they are not labeled; and trying an
AxesLabel->{"x","y","z"} option does not actually produce displayed labels!
Moreover, a mathematician, especially when drawing such a figure on the
blackboard, might not even draw the negative semi-axes, but rather just
the positive semi-axes -- in other words, as the original poster asked,
"showing the first octant".
It's long been VERY annoying to me that the default for Plot3D is a
framed plot, i.e., what suits engineers, physicists, etc., rather than
what simulates the way mathematicians commonly draw such things. And
that it's not easy to reproduce in Mathematica, as a non-default, what
mathematicians commonly do with paper and pencil or chalk and slate.
(Anybody else remember slate?)
Curtis Osterhoudt wrote:
> Hi, Sid,
>
> Does the following give you what you want?
>
> Plot3D[2 - (x^2 + y^2), {x, -2, 2}, {y, -2, 2},
> RegionFunction -> Function[{x, y, z}, x^2 + y^2 <= 2]]
>
> and/or
>
> Plot3D[2 - (x^2 + y^2), {x, -5, 5}, {y, -5, 5}, PlotRange -> {-10, 4},
> Boxed -> False,
> AxesOrigin -> {0, 0, 0}]
>
>
> If these work for you, then it's just a matter of Mathematica choosing its clipping range a bit differently than what you'd like. Note that I haven't checked what the Schaum's figure is like; I'm just guessing!
>
> Best of luck,
> C.O.
>
>
>
> On Monday 08 December 2008 04:22:43 pcoords29 at gmail.com wrote:
>> 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:
- A 3D Plot Query
- From: pcoords29@gmail.com
- Re: A 3D Plot Query
- From: Curtis Osterhoudt <cfo@lanl.gov>
- A 3D Plot Query