1. The problem statement, all variables and given/known data Given that V(t) = π*cos(πt/1.6 + π/6), at which time after t = 0 s is the kinetic energy first at a maximum? The answer is 1.33 seconds. Although, when I put it in the calculator, 1.33s is at a minimum. How would you do this by hand? Step by step work would be appreciated. Thanks! 2. Relevant equations 3. The attempt at a solution I was given the position which was x(t) = 1.6 sin(πt/1.6 + π/6) and took the derivative to get V(t) = π*cos(πt/1.6 + π/6). No clue on how to go from there to get to the maximum.