Sketch the potential function and deduce the phase portrait for the motion under the influence of the following potentials. For each sketch, mark clearly the equilibria (if any), decide on their stability and state the type of orbits (bounded or unbounded). 1. U(x) = x - 3 2. U(x) = (x 1) 2+2 == 3. U(x) = x>0 == 4. U(x, y) = ln x x > 0