Lim căn {{x^2} + x}  - căn x / x^2 bằng

Chọn A

Ta có \[\mathop {\lim }\limits_{x \to {0^ + }} \frac{{\sqrt {{x^2} + x} - \sqrt x }}{{{x^2}}} = \mathop {\lim }\limits_{x \to {0^ + }} \frac{{\left( {{x^2} + x} \right) - x}}{{{x^2}\left( {\sqrt {{x^2} + x} + \sqrt x } \right)}} = \mathop {\lim }\limits_{x \to {0^ + }} \frac{1}{{\sqrt {{x^2} + x} + \sqrt x }} = + \infty \].