计算方阵的行列式则用det函数 DET Determinant DET(X) is the determinant of the square matrix X Use cond instead of det to test for matrix singularity INV Matrix inverse INV(X) is the inverse of the square matrix X. a warning message is printed if X is badly scaled or nearly singular 例:计算方阵的行列式和逆矩阵。 3-31;-35-2;1-21 b=14135;5112;6145; dl=det(a) xl=inv(a) d2=det(b) x2=inv(b) X 1.00001.00001.0000 1.00002.00003.0000 1.00003.00006.0000 d2= 1351 0.1207-0.00370.1118 -0.0348-0.02960.1058 -0.04740.08730.0377 2.广义逆矩阵(伪逆)( Generalized inverse matrix) 般非方阵无逆矩阵和行列式,方程ax=I和xa=I至少有一个无解, 这种矩阵可以求得特殊的逆矩阵,成为广义逆矩阵( general ized inverse matrix)(或伪逆p erse)。矩阵am存在广义逆矩阵xm,使得ax=Imm计算方阵的行列式则用 det 函数。 DET Determinant. DET(X) is the determinant of the square matrix X. Use COND instead of DET to test for matrix singularity. INV Matrix inverse. INV(X) is the inverse of the square matrix X. A warning message is printed if X is badly scaled or nearly singular. 例：计算方阵的行列式和逆矩阵。 a=[3 -3 1;-3 5 -2;1 -2 1]; b=[14 13 5; 5 1 12;6 14 5]; d1=det(a) x1=inv(a) d2=det(b) x2=inv(b) d1 = 1 x1 = 1.0000 1.0000 1.0000 1.0000 2.0000 3.0000 1.0000 3.0000 6.0000 d2 = -1351 x2 = 0.1207 -0.0037 -0.1118 -0.0348 -0.0296 0.1058 -0.0474 0.0873 0.0377 2． 广义逆矩阵（伪逆）(Generalized inverse matrix) 一般非方阵无逆矩阵和行列式，方程 ax=I 和 xa=I 至少有一个无解， 这种矩阵可以求得特殊的逆矩阵，成为广义逆矩阵(generalized inverse matrix)（或伪逆 pseudoinverse）。矩阵 amn存在广义逆矩阵 xnm，使得 ax=Imn