设D是单位圆盘，即D={(x，y)|x+y≤1}，那么∫∫D(1+x+y)dxdy=____.()
A.∫0πdθ∫01(1+r2)dθ B.∫01dθ∫02πln(1+r2)rdr C.∫02πdθ∫01ln(1+r2)rdr D.∫012πln(1+r2)dr正确答案C
设D是单位圆盘，即D={(x，y)|x+y≤1}，那么∫∫D(1+x+y)dxdy=____.()
A.∫0πdθ∫01(1+r2)dθ B.∫01dθ∫02πln(1+r2)rdr C.∫02πdθ∫01ln(1+r2)rdr D.∫012πln(1+r2)dr正确答案C
