1. The problem statement, all variables and given/known data Hello, I have been tasked with the next problem, I have to prove that the next two integrals are complex numbers; but I have no idea of how to attack this problem. 2. Relevant equations ∫dx f*(x) x (-ih) (∂/∂x) f(x) integrating between -∞ and ∞ ∫dx f*(x) (-ih) (∂/∂x) (x f(x)) integrating between -∞ and ∞ Where h is a constant, i = √-1 and f* the complex conjugate of the function f 3. The attempt at a solution Well, the only thing I can think of for solving is a direct integration by parts, using u =f* x and dv= (∂/∂x) f(x) dx for the first integral, with du=f* and v= ∫(∂/∂x) f(x)dx=f(x). But then, I find that -ih∫u dv= uv -∫v du = -ih( [f f* x]-∞∞+∫f f*dx). f f*=1, so I find myself with -ih[(∞) (∞-∞)] All help is appreciated.