An anti-hermitian (or skew-hermitian) operator is equal to minus its hermitian conjugate: ...

An anti-hermitian (or skew-hermitian) operator is equal to minus its hermitian conjugate:

 [3.95]

(a) Show that the expectation value of an anti-hermitian operator is imaginary.

(b) Show that the commutator of two hermitian operators is anti-hermitian. How about the commutator of two anti-hermitian operators?