Why am I getting negative zero as an eigen value while using the 'eig' function?

Hi all

I ran the following code which makes use of the 'eig' function and I encountered a negative zero in the value printed out by it. Is this valid? If yes, what does the negative sign signify?

a=[1 2 3;1 2 3; 1 2 3]
eig(a)

This gives me the following output:

ans =

    6.0000
    0.0000
   -0.0000

Thanks in advance.

Answer 1

[Steven Lord]

Change your display format and you'll see that the third element of that vector is very small in magnitude and negative but not exactly 0.