Źródło TeX:

\underset{x\rightarrow+ \infty}{\lim }\,\dfrac{\sqrt{x^2+1}}{x}=\underset{x\rightarrow+ \infty}{\lim }\,\dfrac{\sqrt{x^2+1}}{\sqrt{x^2}}=\underset{x\rightarrow +\infty}{\lim }\,\sqrt{1+\dfrac{1}{x^2}}=1