Apotential energy function is given by u = a x3 + b x2 − c x + d . for positive parameters a, b, c, d this potential has two equilibrium positions, one stable and one unstable. find the stable equilibrium position for a = 1.45 j/m3 , b = 2.85 j/m2 , c = 1.7 j/m , and d = 0.6 j . answer in units of m