1. The problem statement, all variables and given/known data http://i.minus.com/jCH20SF290QIb.png [Broken] 2. Relevant equations Critical point: when the derivative = 0 or the derivative fails to exist. 3. The attempt at a solution I got x = 0 and x = e as critical points. When x = e, the function becomes 0 / e, which = 0. Therefore, e is a critical point of f. When x = 0, the function becomes 1/0, which = ∞. The derivative of ∞ does not exist, so wouldn't x = 0 be a critical point? The answer key disagrees; the only critical point the key provides is x = e.