NuN= lsn Isn=A(GUs-1s 即 G11G12 In nI 1 G21G22···●G2n 2 22 m2●●●●n n n nnn G G G G G G G G G • • • • • • • • • • • • • • • • • • • • • • 1 2 21 22 2 11 12 1 nnnn UUU•• 21 Inn II•• 22 11 = 即： Gn Un = Isn Isn = A (GUS − IS )