(a) Prove that a Jordan block matrix $J_{0, n}$ with zero diagonal entries is nilpotent, as in Exercise 1.3.12. (b) Prove that a Jordan matrix is nilpotent if and only if all its diagonal entries are zero. (c) Prove that a matrix is nilpotent if and only if its Jordan canonical form is nilpotent. its only eigenvalue is 0 .
(d) Explain why a matrix is nilpotent if and only if