西安毛子科技大学XIDIANUNIVERSITYA.0XEkDX112于是=E.BX0CX = A-1即[AX=EXiz = 0AX12 = 0L二X21 = -B-'CA-1CXi + BX21 = 0X2 = 0BX22 = E,A-10D-B-1-B-ICA-1( ) 11 12 21 22 0 0 , 0 k r A X X E C B X X E       =       于是 即 11 12 11 21 22 0 0 k r AX E AX CX BX BX E  =   =   + =    = 1 1 1 1 1 A 0 D B CA B − − − − −    =     − . 1 11 12 1 1 21 22 0 0 X A X X B CA X − − −  =   =   = −    =