MATLAB: How do you get a general solution of and underdetermined system

underdetermined system

How can you obtain the general solution of an underdetermined system? What I have now is:
A=[1 2 3;-2 -1 0;0 2 4];
b=[5;-1;6];
x=A\b
but this gives me the answer x =
   NaN
   NaN
   NaN
hope someone can help me

Best Answer

I would use the pseudo-inverse pinv function:
x = pinv(A)*b
x =
     166.6667e-003
     666.6667e-003
       1.1667e+000
There may be other options, such as the sparse matrix lsqr funciton, which gives the same result:
x = lsqr(A,b)
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