类似地: D 12 =a12-412421 C ∑(-1) 2
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 In D 22 n2 z(ij2…jn) 2j2
n n n n n n a a a a a a a a a D 1 2 2 1 2 2 2 1 1 1 2 1 = n n j j nj 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 0 D l1c22 0 0 D 2 22 n 2
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) 0 D3= 02n-1a 2n z(nn-1…21) 2n-1
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