3非奇异矩阵 设A为方阵 11 12 A 2 nnn×n A的逆矩阵为:HA|4≠03.非奇异矩阵 设A为方阵 A的逆矩阵为： 11 12 1 21 22 2 1 2 n n n n nn n n a a a a a a A a a a      =           1 , 0 A A A A  − = 