积分区域D如下图所示:I= ? D xydxdy= ∫ dx ∫ xydy = ∫ x 2 [(1+ 1?x2 )2?x2]dx = ∫ (x?x3+x 1?x2 )dx=( x2 2 ? x4 4 ? 1 3 (1?x2) 3 2 ) | = 7 12 .
简单分析一下,答案如图所示