Which has most stable +2 oxidation state?

Which one is most ionic

Number of paired electrons in O₂ molecules is

$$\,3{\left( {\sin x - \cos x} \right)^4} + 6{\left( {\sin x + \cos x} \right)^2} + 4\left( {{{\sin }^6}x + {{\cos }^6}x} \right) = $$