Źródło TeX:

\lim\limits_{x\to +\infty }(\pi\, x-2x\,\text{arctg} x)=\left[\infty-\infty\right] = \lim\limits_{x\to +\infty }x\,(\pi\,-2\,\text{arctg} x)=\left[ \infty\cdot 0\right]