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Câu hỏi: Tìm $\underset{x\Rightarrow +\infty }{\mathop{\lim }} \dfrac{2x+1}{x-1}.$
A. 3.
B. 1.
C. $-1.$
D. 2.
A. 3.
B. 1.
C. $-1.$
D. 2.
Ta có $\underset{x\Rightarrow +\infty }{\mathop{\lim }} \dfrac{2x+1}{x-1}=\underset{x\Rightarrow +\infty }{\mathop{\lim }} \dfrac{x\left( 2+\dfrac{1}{x} \right)}{x\left( 1-\dfrac{1}{x} \right)}=\underset{x\Rightarrow +\infty }{\mathop{\lim }} \dfrac{2+\dfrac{1}{x}}{1-\dfrac{1}{x}}=2.$
Đáp án D.