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a) \(\mathop {\lim }\limits_{x \to – 3} \root 3 \of {{{{x^4} + 27x} \over {4{x^2} – 36}}} \) là
(A) \( – {3 \over 2};\) (B) \({3 \over 4};\)
(C) \( – {3 \over 4};\) (D) \({3 \over 2}.\)
b) \(\mathop {\lim }\limits_{x \to – \infty } {{\root 3 \of {{x^3} + 2{x^2} + 1} } \over {\sqrt {2{x^2} + 1} }}\) là
(A) \({{\sqrt 2 } \over 2};\) (B) \(1;\)
(C) \(0;\) (D) \( – {{\sqrt 2 } \over 2}.\)
c) \(\mathop {\lim }\limits_{x \to – 1} {{{x^2} + 1} \over {\left( {{x^2} + x} \right)\left( {{x^3} + 1} \right)}}\) là
(A) \( + \infty ;\) (B) \(2;\)
(C) \( – \infty ;\) (D) \( – 2.\)
d) \(\mathop {\lim }\limits_{x \to {{\left( { – 3} \right)}^ + }} {{{x^2} + 13x + 30} \over {\sqrt {\left( {x + 3} \right)\left( {{x^2} + 5} \right)} }}\) là
A) \(2;\) (B) \(0;\)
(C) \( – 2;\) (D) \({2 \over {\sqrt {15} }}.\)
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e) \(\mathop {\lim }\limits_{x \to 7} {{3 – \sqrt {x + 2} } \over {{x^2} – 2x – 35}}\) là
A) \( – {1 \over {72}};\) (B) \( – {1 \over {12}};\)
(C) \(0;\) (D) \({1 \over {52}}.\)
f) \(\mathop {\lim }\limits_{x \to – \infty } \left( {\sqrt {5{x^2} + 2x} + x\sqrt 5 } \right)\) là
A) \(0;\) (B) \( – {{\sqrt 5 } \over 5};\)
(C) \( + \infty ;\) (D) \( – \infty .\)
a) Chọn D b) ChọnD c) Chọn C
d) Chọn B e) Chọn A f) Chọn B