Tính Lim 4{x^5} - 3{x^3} + x + 1}

Chọn D

\(\mathop {\lim }\limits_{x \to - \infty } \left( {4{x^5} - 3{x^3} + x + 1} \right) = \mathop {\lim }\limits_{x \to - \infty } {x^5}\left( {4 - \frac{3}{{{x^2}}} + \frac{1}{{{x^4}}} + \frac{1}{{{x^5}}}} \right) = - \infty .\)

Vì \(\mathop {\lim }\limits_{x \to - \infty } {x^5} = - \infty ;\mathop {\lim }\limits_{x \to - \infty } 4 - \frac{3}{{{x^2}}} + \frac{1}{{{x^4}}} + \frac{1}{{{x^5}}} = 4\).