Źródło TeX:

\underset{x\rightarrow +\infty }{\lim }\, \dfrac{(x)'}{(\ln x)'} = \underset{x\rightarrow +\infty }{\lim }\, \dfrac{1}{\frac{1}{x}} =\underset{x\rightarrow +\infty }{\lim }\, x = +\infty