MATLAB: Hi every one! I have inversed matrix invA from the matrix A (det(A)=!0), but invA*A =! I (identity matrix). Please explain me why

inverse matrix

Iam solving the equation A*x=b, Here is A =
   1.0e+07 *
    0.3411    0.0393   -0.3411    0.0393         0         0
    0.0393    0.0061   -0.0393    0.0029         0         0
   -0.3411   -0.0393    3.7368   -0.0342   -3.3956    0.0051
    0.0393    0.0029   -0.0342    0.1307   -0.0051   -0.1246
         0         0   -3.3956   -0.0051    3.3956   -0.0051
         0         0    0.0051   -0.1246   -0.0051    0.1246

Best Answer

Hi Cong Dang, most probably your matrix is badly conditioned (meaning that there are some almost linearly dependent columns).
What is the result of
rank(A)
where A is your matrix?
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