类似地: D= 12 1122 12 ∑(-1)02
类似地： 21 22 11 12 a a a a D = = a11a22 − a12a21 1 2 1 2 1 2 ( ) ( 1) j j j j = − a a
定义23n阶行列式 11 12 D 2 2 nn =∑(-1) z(ij2…jn) 小12J2
n n n n n n a a a a a a a a a D 1 2 21 22 2 11 12 1 = n n j j n j j j j a a a = − 1 2 1 2 1 2 ( ) ( 1) 定义2.3 n阶行列式
例1计算下列n阶行列式 1c22 nn C/S2 22 0 D l022 n2
例1 计算下列n阶行列式 an n a a D 22 11 1 = 0 0 = a11 a22 ann an an an n a a a D 1 2 21 22 11 2 = 0 = a11 a22 ann
(n-1)+(n-2) 2+1 (n-1+1) (n-1) 0 2n (nn-1…21) In 2n-1 nn
n n n n n n n n a a a a a a D 1 1 2 1 2 1 3 − − = 0 = (−1) (n n−1 2 1) a1n a2n−1 an1 (n −1) + (n − 2) ++ 2 +1 ( 1) 2 ( 1 1) − − + = n n