when det(A)=0 ,why MATLAB can define inverse for matrix?

[m.azangoo]

Why in MATLAB when we define A matrix as

A=[1 2 3;4 5 6;7 8 9]

whereas det(A)=0 (determinant(A)=0) , it give us this result for inverse of A:

inv(A)=
ans =
1.0e+016 *

-0.4504 0.9007 -0.4504
0.9007 -1.8014 0.9007
-0.4504 0.9007 -0.4504

why we have inverse when det(A)=0

What kind of algorithm matlab use to define inverse of matrix?


thanks for your attention

 

[zorro]

Hi m.azangoo,

note that when you request inv(A) the following warning message is printed (at least in release 14):

Warning: Matrix is close to singular or badly scaled.
Results may be inaccurate. RCOND = 2.203039e-018.

Type "doc inv" in the command window in order to access to the help page with details about the algoritms user.
regards

Z