The trace of a square n x n matrix a = (a_ij) is the sum a11 + a22 ++ ann of the entries on its main diagonal. let v be the vector space of all 2 x 2 matrices with real entries. let h be the set of all 2 x 2 matrices with real entries that have trace 0. is h a subspace of the vector space v? is h closed under addition? if it is, enter closed. if it is not, enter two matrices in h whose sum is not in h, using a comma separated list and syntax such as ,, , for the answer [1324],[5768]. (hint: to show that h is not closed under addition, it is sufficient to find two idempotent matrices and such that +≠+