Suppose that the internuclear distance may be written R=R_e+x where R_e is the equilibrium bond length. Also suppose that the potential well is symmetrical and confines the oscillator to small displacements. Deduce expressions for 1/〈R〉², 1/〈R²〉, and 〈1/R²〉 to the lowest non-zero power of 〈x²〉/R_e² and confirm that values are not the same.