A bad calculator ?
During office hours, a student once tried an online calculator to check on the eigenvectors of the matrix3 -1 -1 -1 -1 2 -1 0 -1 -1 3 -1 -1 0 -1 2Here it the command Link The result
{{4, 4, 2, 0}, {{-2, 1, 0, 1}, {-1, 0, 1, 0}, {0, -1, 0, 1}, {1, 1, 1, 1}}}
of the Mathematica command
Eigensystem[{{3,-1,-1,-1},{-1,2,-1,0},{-1,-1,3,-1},{-1,0,-1,2}}]
Still, both outputs are right? How come? Related, an other student sent the following screenshot of a calculation. We had learned that B=A10 has the same eigenvectors than A. How come the results change? Again, its up to you to find the problem:
