Giải thích các bước giải:
\(\begin{array}{l}
\lim \frac{{\sqrt {{n^2} + 2} + \sqrt {{n^2} - 1} }}{{{n^2} + 2 - {n^2} + 1}}\\
= \lim \frac{{\sqrt {{n^2} + 2} + \sqrt {{n^2} - 1} }}{3}\\
= \lim \frac{{\sqrt {1 + \frac{2}{{{n^2}}}} + \sqrt {1 - \frac{1}{{{n^2}}}} }}{{\frac{3}{n}}}\\
= \lim \frac{n}{3}.\left( {\sqrt {1 + \frac{2}{{{n^2}}}} + \sqrt {1 - \frac{1}{{{n^2}}}} } \right) = + \infty \\
Do:\mathop {\lim }\limits_{x \to + \infty } \frac{n}{3} = + \infty \\
\lim \left( {\sqrt {1 + \frac{2}{{{n^2}}}} + \sqrt {1 - \frac{1}{{{n^2}}}} } \right) = 2
\end{array}\)
