(S+2)a1(S)-l2(S) 4s1(s)+4(S+1)l2(s) s+2 写戚矩阵形式 u,s 2 4 4s4(s+)n2(s S s+22 4 ( ) 4( 1) ( ) 4 1 1 ( 2) ( ) ( ) 1 2 1 2 2 + − + + = + − = + s s su s s u s s s u s u s           + + =            − + + − 2 4 1 1 ( ) ( ) 4 4( 1) ( 2) 1 2 2 1 s s s u s u s s s s 写成矩阵形式