If AAA is a n×nn \times nn×n matrix, which of the following is always equivalent to tr(A2)\text{tr}(A^2)tr(A2)?
(tr(A))2(\text{tr}(A))^2(tr(A))2
The sum of the squares of the eigenvalues of AAA.
det(A)2\det(A)^2det(A)2
The sum of the squares of the entries of AAA.