1. The problem statement, all variables and given/known data Calculate <x> for the Gaussian wave packet [itex]\psi(x)=Ne-(x-x0)/2k2[/itex] 2. Relevant equations [itex]\left\langle x \right\rangle = \int dx x|\psi(x)|2[/itex] 3. The attempt at a solution So I've been reviewing for the up-coming midterm and I've had the painful realization that I'm basically killing myself with basic issues; in this case solving the integral. [itex]\left\langle x \right\rangle = \int dx x|\psi(x)|2 = \int dx x|Ne-(x-x0)/2k2|2 =N2\int dx x|e-(x-x0)/2k2|2[/itex] It's at this point that I know there a u substitution to be made (at least I'm pretty sure that's the best way to solve the integral), but I'm not exactly sure for which value? Is there a better way to solve this integral? Thanks for any pointers!