A square matrix A is nilpotent if A" = 0 for some positive integer n. Let V be the vector space of all 2 × 2 matrices with real entries. Let H be the set of all 2 × 2 nilpotent matrices with real entries. Is H a subspace of the vector space V? 1. Is H nonempty? H is nonempty ♥ O 2. 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 [[1,2],[3,4]], [[5,6],[7,8]] for the answer 6] (Hint: to show that H is not closed under addition, it is sufficient to find two nilpotent matrices A and B such that (A + B)" + 0 for all positive integers n.) 3. Is H closed under scalar multiplication? If it is, enter CLOSED. If it is not, enter a scalar in R and a matrix in H whose product is not in H, using a comma separated list and syntax such as 2, [[3,4], [5,6]] for the answer 2, (Hint: to show that H is not closed under scalar multiplication, it is sufficient to find a real number r and a nilpotent matrix A such that (rA)" + 0 for all positive integers n.)