Homework Statement
The demonstration for the momentum operator in Quantum Mechanics goes something like this
<v>=\frac{d}{dt}<x>=\frac{d}{dt} \int x \Psi^* \Psi dx
and then one ends up with
<p>=m<v>=\int \Psi^* (-i \hbar \frac{d}{dx}) Psi dx
however, if you swap the congugates you get...