设D:{01(2)r52(O,则 D (⊙) c≤6≤B f(rcos e, rsinO)drdo q1(6) D 6) do f(rcos e, rsinO)rdr 1() r=02() 特别,对D 0≤r≤(() 1( 0≤6<2丌 ∫ rcos 0, rsinOrdrde dD C2n de)/(rcos e, rsin O)rdro HIGH EDUCATION PRESS 机动目录上页下页返回结束  D o ( ) r =1  ( ) r =2  ( )  r =1   o ( )  r =2  ( ) ( ) 2 1 ( cos , sin ) d     f r  r  r r 设 , ( ) ( ) : 1 2             r   D 则 D f (r cos,rsin )r d r d  =   d 特别, 对            0 2 0 ( ) : r D D f (r cos,rsin )r d r d  ( ) 0 ( cos , sin ) d   f r  r  r r  =   2 0 d r =( ) o D 机动 目录 上页 下页 返回 结束