I don't know how to evaluate this limit. There doesn't seem to be anything obvious to do. And what I'm about to show you, I guess you could view it as a little bit of a trick. I can't claim that I would have figured it out on my own, maybe eventually if I were spending hours on it. And I'm assuming somebody was fumbling with it long enough they said, oh wait, wait, look, if I just add and subtract the same term here, I can begin to algebraically manipulate it and get it to what we all know is the classic product rule. So what do I add and subtract here? Well, let me give you a clue.