Re: How to specify these limits in an integral?
- To: mathgroup at smc.vnet.net
- Subject: [mg63455] Re: How to specify these limits in an integral?
- From: "Jean-Marc Gulliet" <jeanmarc.gulliet at gmail.com>
- Date: Sun, 1 Jan 2006 01:16:08 -0500 (EST)
- Organization: The Open University, Milton Keynes, U.K.
- References: <dp5rch$rjs$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
"Konrad Den Ende" <chamster at home.se> a écrit dans le message de news: dp5rch$rjs$1 at smc.vnet.net... | | I have a double integral of the function f = x * y. I'd | like make Mathematica compute it's value over the | disc specified by, let's say: | x^2 + y^2 - 2x + 6y <=6 | | I can carry out computation on paper, preparing the | sutabile substitutions myself but i wonder if there's | a way to shove it all into Mathematica and let it chew. | | Sincerely | Konrad | | Hi Konrad, Have a look at the *Boole* function (http://documents.wolfram.com/mathematica/functions/Boole) and at the _Mathematica_Book_, section "3.5.9 Integrals over Regions" (http://documents.wolfram.com/mathematica/book/section-3.5.9). In your case you could write your integral as In[1]:= f[x_, y_] := x*y In[2]:= Integrate[f[x, y]*Boole[x^2 + y^2 - 2*x + 6*y <= 6], {x, -10, 10}, {y, -10, 10}] Out[2]= -48*Pi Best regards, /J.M.