Tính giới hạn Lim {2x + 3/ căn {2{x^2} - 3} }}\)

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Tính giới hạn\(\mathop {\lim }\limits_{x \to - \infty } \frac{{2x + 3}}{{\sqrt {2{x^2} - 3} }}\)

\(\frac{1}{{\sqrt 2 }}\).

\( - \frac{1}{{\sqrt 2 }}\).

\(\sqrt 2 \).

\( - \sqrt 2 \).

Giải thích

ChọnD.Ta có\[\mathop {\lim }\limits_{x \to - \infty } \frac{{2x + 3}}{{\sqrt {2{x^2} - 3} }} = \mathop {\lim }\limits_{x \to - \infty } \frac{{x(2 + \frac{3}{x})}}{{|x|\sqrt {2 - \frac{3}{{{x^2}}}} }} = \mathop {\lim }\limits_{x \to - \infty } \frac{{x(2 + \frac{3}{x})}}{{ - x\sqrt {2 - \frac{3}{{{x^2}}}} }} = \mathop {\lim }\limits_{x \to - \infty } - \frac{{2 + \frac{3}{x}}}{{\sqrt {2 - \frac{3}{{{x^2}}}} }} = \sqrt 2 \]