39. (2023•唐山三模)已知曲线y=lnxy=lnxy=lnx与y=ax2(a>0)y=ax^{2}(a>0)y=ax2(a>0)有公共切线,则实数aaa的取值范围为 ___[12e,+∞)[{\frac{1}{2e},+\infty })[2e1,+∞)___.