Re: How to integrate a function over a polygon
- To: mathgroup at smc.vnet.net
- Subject: [mg123312] Re: How to integrate a function over a polygon
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Thu, 1 Dec 2011 05:51:11 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201111291203.HAA05398@smc.vnet.net> <201111300820.DAA17132@smc.vnet.net> <op.v5rsylgetgfoz2@bobbys-imac.local>
Note that you are plotting a pair:
{x^2 + y^2, 0}
The 0 gives the triangle. It was my doing really, no need to blame Mathematica ;-)
Andrzej
On 30 Nov 2011, at 18:45, DrMajorBob wrote:
> When I plot that:
>
> Plot3D[{x^2 + y^2, 0}, {x, -3, 3}, {y, -3, 3},
> RegionFunction -> Function[{x, y, z}, 0 < x < 1 && 0 < y <= x]]
>
> I see the 3D surface and, in addition, I see a triangle on the z == 0 plane marking the region.
>
> I didn't expect the triangle. What am I missing in the documentation?
>
> Bobby
>
> On Wed, 30 Nov 2011 02:20:39 -0600, Andrzej Kozlowski <akoz at mimuw.edu.pl> wrote:
>
>>
>> On 29 Nov 2011, at 13:03, Mikael wrote:
>>
>>> In a related question I wonder how one can plot g[x,y] over only the
>> 2-dimensional unit simplex.
>>
>>
>> Do you mean something like this:
>>
>> Plot3D[{x^2 + y^2, 0}, {x, -3, 3}, {y, -3, 3},
>> RegionFunction -> Function[{x, y, z}, 0 < x < 1 && 0 < y <= x]]
>>
>> ? >>
>
>
> --
> DrMajorBob at yahoo.com