1. The problem statement, all variables and given/known data i'm sorry i know i've been bombarding physics forums with questions but i need help :p using reverse product rule [tex]\int uv'[/tex] = uv - [tex]\int vu'[/tex] and say i have a*b i noticed my teaher said that a=u and b=v not v' and he simly made that into a v' by deriving. is there a point to this if so what is the point and is this something he is likely to have done on purpose or by accident. 2. Relevant equations ....and yes a*b = e^-y /y 3. The attempt at a solution i attempted, but failed miserably.