um=am(t)u(rdr am()u, (tdt 0 am()u, (dc 0 (tu(tdt 0令 a  u  d t u m f m ( ) ( ) 0  =                     =               =             a u d t a u d t a u d t u u u u m p f m f m f m p m m m ( ) ( ) 0 ( ) ( ) 0 ( ) ( ) 0 2 1 2 1  