1. The problem statement, all variables and given/known data Wavefunction is of form: ψ(x) = eikx Find momentum and energy of this state. 2. Relevant equations Fourier transform of ψ(x) to get to momentum space or is it <p> = integral from -infinity to infinity of ψ* (h/i) * derivative wrt x of ψ dx 3. The attempt at a solution I initially tried the second approach, but it didn't work, I got an infinite answer. Someone said to instead convert the function to momentum space, I used the Fourier transform but when I do that, my integral in the Fourier transform is -infinity to infinity of an oscillating function that doesn't decrease and is undefined. I have no idea now how to proceed. I've worked on this question for hours, I searched the textbook, google, etc. and could not find anything useful.