1. The problem statement, all variables and given/known data In the textbook I am studying one of the exercises is: lim x→0 e-x - 1 / x = ? The answer given is -1. But I can't see why this answer should follow. 2. Relevant equations The most relevant equation here is: lim x→0 = ex - 1 / x = 1 3. The attempt at a solution So let's take: lim x→0 e-x - 1 / x = ? So x approximates 0, so you get e-x approximates e-0 which in my view is just e0 = 1. Therefore I don't see how this differs from lim x→0 = ex - 1 / x = 1. In my view the answer should be 1 and not -1... I'm clearly missing something, but I don't have a clue what... Can you please help me?