1. The problem statement, all variables and given/known data problem in attachment 2. Relevant equations 3. The attempt at a solution I can get f'(x) as sqrt(1 + (sinx)^2) and derive that to get the second derivative but as far as that I don't really get the concept behind this question will y be another function I have to use chain rule with? or is it just a variable and I plug in pi/6 normally?