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Problem IV (15 points) Consider the following 2nd order nonlinear equation x" - x3 +4x = 0. 1. (5 points) Write equation as a 2 x 2 hamiltonian system and write down its energy (hamiltonian) function. 2. (10 points) If x(t) is a solution with initial condition r(0) = 0, x'(0) = -2v2, find the limit limt-+too x(t)