Y=AX=ABY=(AB)Y, X=BY= BAX=(BA)X, 从而可知AB=E=BA, 正如数一样若ab=ba=1,则a=b-1,b=a-1, 记B=A-,称其为逆矩阵 KY = AX = ABY = (AB)Y, X = BY = BAX = (BA)X, 从而可知 AB = E = BA, , 1, , , −1 −1 正如数一样 若ab = ba = 则a = b b = a , . 记B = A −1 称其为逆矩阵