help with integration

*To*: mathgroup at smc.vnet.net*Subject*: [mg121632] help with integration*From*: Salman Durrani <dsalman96 at yahoo.com>*Date*: Fri, 23 Sep 2011 03:43:15 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

I am trying to do the following integration: Integrate[r^2*ArcCos[x/r] - x*Sqrt[r^2 - x^2], {x, Sqrt[3] y, Sqrt[r^2 - y^2]} ] When I try, Mathematica comes back to be with a very long conditional expression. How do I tell mathematica that r is positive, real in the above equation not complex. Thanks Kahless

**Follow-Ups**:**Re: help with integration***From:*Heike Gramberg <heike.gramberg@gmail.com>

**Re: help with integration***From:*Richard Hofler <rhofler@bus.ucf.edu>