1. The problem statement, all variables and given/known data A single conservative force F(x) acts on a 2.4 kg particle that moves along an x axis. The potential energy U(x) associated with F(x) is given by U(x) = -4xe-x/4 where x is in meters. At x = 5.0 m the particle has a kinetic energy of 5.2 J. (a) What is the mechanical energy of the system? (b) What is the maximum kinetic energy of the particle and (c) the value of x at which it occurs? 2. Relevant equations Emech=K+U 3. The attempt at a solution I know how to find the mechanical energy, but I don't know how to do the derivative of U(x) so that I can do b) and c) even though its simple.