Tính lim x → 4 √ x − 2 /(x − 4)
Giải thích
\(\mathop {\lim }\limits_{x \to 4} \frac{{\sqrt x - 2}}{{x - 4}} = \mathop {\lim }\limits_{x \to 4} \frac{{\sqrt x - 2}}{{(\sqrt x - 2)(\sqrt x + 2)}} = \mathop {\lim }\limits_{x \to 4} \frac{1}{{\sqrt x + 2}} = \frac{1}{4}.\)