上区域特征如图r=9 D r=02() a≤6≤B, q1(6)sr≤q2( yB (rcos b, sino)rdrde =∫ q2(6) de f(rcos o, sino)rdr. 1(0) 上页区域特征如图      , ( ) ( ). 1   r  2  ( cos , sin ) . ( ) ( ) 2 1   =       d f r  r  rdr  D f (r cos ,rsin )rdrd   o A D ( ) 2 r =   ( ) 1 r =  