1. The problem statement, all variables and given/known data I just had a test I can't remember exactly how the question went but it was a relatively easy differentiation problem. I can only remember my result, which was y' = 2sinxcosx - sinx 2. Relevant equations 3. The attempt at a solution I noticed that 2sinxcosx is also sin2x so you could rewrite it as Sin2x - Sinx Now, to find the places where the slope is 0 i obviously just set it to 0 and solve. My problem was that I didn't know if I should go the Sin2x - Sinx route or Factor out a sine and do it like thisL sinx(2cosx -1) = 0 cosx = 1/2 x = ∏/3 +2∏k x = 5∏/3 + 2∏k where k is any integer The above one is the route I chose to take at the end. However, if I solve for sin2x - sin x = 0 I can just say, ∏k, where k is any integer? Where is my logic flawed?