设A=1-1-111-1111,利用初等行变换求A逆

1 -1 -1 1 0 0 1 -1 -1 1 0 0 1 -1 -1 1 -1 -1 1 0 0 0.5 -1 -0.51 1 -1 0 1 0 = 0 2 0 -1 1 0 = 0 1 0 -0.5 0.5 0 = 0 1 0 -0.5 0.5 01 1 1 0 0 1 0 2 2 -1 0 1 0 1 1 -0.5 0 0.5 0 0 1 0 -0.5 0.5【1】②-①，③-①【2】②/2，③/2【3】①+③，③-②. 0.5 -1 -0.5A的逆矩阵= -0.5 0.5 0 0 -0.5 0.5