Why I got inumr??

*To*: mathgroup at smc.vnet.net*Subject*: [mg80987] Why I got inumr??*From*: "hj.gegewu" <chiron1201 at 163.com>*Date*: Fri, 7 Sep 2007 02:03:46 -0400 (EDT)

Hi all! I have a problem when I try to Nintegrate following code: a = 0; b = 2; P = (Max[0, (Min[b, #2*Cos[#3] + Sqrt[#1^2 - (#2*Sin[#3])^2]] - Max[a, #2*Cos[#3] - Sqrt[#1^2 - (#2*Sin[#3])^2]])/(b - a)]) &; ProbR1 = (NIntegrate[ P[(-#1*Cos[z] + Sqrt[#2^2 - (#1 *Sin[z])^2])/#3, x, y]/(4*Pi^2*(b - a)), {z, Pi - ArcSin[#2/#1], Pi + ArcSin[#2/#1]}, {y, 0, 2*Pi}, {x, a, Min[b, (-#1*Cos[z] + Sqrt[#2^2 - (#1 *Sin[z])^2])/(#3* Abs[Sin[y]])]}, Method -> {"GlobalAdaptive", "SingularityHandler" -> "DuffyCoordinates"}]) &; ProbR2 = (NIntegrate[ P[(-#1*Cos[z] - Sqrt[#2^2 - (#1 *Sin[z])^2])/#3, x, y]/(4*Pi^2*(b - a)), {z, Pi - ArcSin[#2/#1], Pi + ArcSin[#2/#1]}, {y, 0, 2*Pi}, {x, a, Min[b, (-#1*Cos[z] + Sqrt[#2^2 - (#1 *Sin[z])^2])/(#3* Abs[Sin[y]])]}, Method -> {"GlobalAdaptive", "SingularityHandler" -> "DuffyCoordinates"}]) &; ProbR1[130, 125, 50] ProbR2[130, 125, 50] while the line of "ProbR1[130, 125, 50]" can be caculated correctly, the line of "ProbR2[130, 125, 50]" keeps giving me the warning of NIntegrate::inumr: "The integrand \ Max[0,1/2\(-Max[0,Times[<<2>>]+Times[<<2>>]]+Min[2,x\Cos[<<1>>]+Sqrt[\ Plus[<<2>>]]])]/(8\\[Pi]^2) has evaluated to non-numerical values for \ all sampling points in the region with boundaries \ {{0.5,0.75},{0.125,0.0625},{0.5,0.25}}." The only difference of these two sentence is the sign of "Sqrt[#2^2 - (#1 *Sin[z])^2])". Why this happened? Thanks!