Hello everybody, long time reader, first time poster. I've searched the forums extensively (and what seems like 60% of the entire internet) for anything relevant and haven't found anything, please point me in the right direction if you've seen this before! 1. The problem statement, all variables and given/known data Show that even though Q and R are Hermitian operators, QR is only Hermitian if [Q,R]=0 2. Relevant equations [Q,R] = QR - RQ [Q,R]* = R*Q*-Q*R* 3. The attempt at a solution I've managed to prove, using the definition of Hermiticity that: ∫f(i(QR-RQ))g dτ = ∫g(i(QR-RQ))*f dτ For two random functions, f and g, and i= Sqrt(-1) But I'm not sure how relevant this is... I don't have a strong enough intuition to see whether or not this immediately proves anything. Any help would be greatly appreciated!