2223 23 22 a 13 32a3 33 32 =a1(-1) 1+122223 +a12(-1) 1+22123 32 33 33 +a13(-1) 1+3121 2 32 记为 1+3 11 (-1)4+1M1+a12(-1)1+2 M1+a12(-1)1中M 12 3 13 记为 ==a141+a12412+a13413 称M1,M12,M13和41,A12,A13分别是 a1,a2,a1的余子式和代数余子式3 1 3 2 2 1 2 2 1 3 3 1 3 3 2 1 2 3 1 2 3 2 3 3 2 2 2 3 1 1 a a a a a a a a a a a a a a = a − + 3 1 3 2 1 3 2 1 2 2 1 3 3 1 3 3 1 2 2 1 2 3 1 2 3 2 3 3 1 1 2 2 2 3 1 1 ( 1) ( 1) ( 1) a a a a a a a a a a a a a a a + + + + − = − + − 13 1 3 12 13 1 2 11 12 1 1 11 a ( 1) M a ( 1) M a ( 1) M + + + = = − + − + − 记 为 = = a11A11 + a12A12 + a13A13 记为 称M11, M12, M13和A11, A12, A13分别是 , , . a11 a12 a13的余子式和代数余子式