1. The problem statement, all variables and given/known data http://i.minus.com/jbicgHafqNzcvn.png [Broken] 2. Relevant equations The limit definition of a derivative: [f(x+h)-f(x)]/h as h approaches zero is f'(x) 3. The attempt at a solution I'm just not understanding the wording of the question. The limit given in the question is indeed equal to g'(x) since it's set up properly and indeed sec(pi) is -1 and subtracting -1 makes it a positive 1.