Re: How to integrate a function over a polygon
- To: mathgroup at smc.vnet.net
- Subject: [mg123332] Re: How to integrate a function over a polygon
- From: Bob Hanlon <hanlonr357 at gmail.com>
- Date: Fri, 2 Dec 2011 07:19:35 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201111291203.HAA05398@smc.vnet.net>
You are plotting two functions. The triangle is the plot of the
constant zero restricted to the triangular region defined by the
RegionFunction.
Bob Hanlon
On Thu, Dec 1, 2011 at 5:50 AM, DrMajorBob <btreat1 at austin.rr.com> 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
>