Câu hỏi: Tính ${\lim \dfrac{{{n^2} - 2n + 6}}{{4{n^2} + 3}}}$. A. ${2}$. B. ${\dfrac{1}{4}}$. C. ${ + \infty }$. D. ${4}$.
Ta có: $\lim \dfrac{{{n}^{2}}-2n+6}{4{{n}^{2}}+3}=\lim \dfrac{1-\dfrac{2}{n}+\dfrac{6}{{{n}^{2}}}}{4+\dfrac{3}{{{n}^{2}}}}=\dfrac{1-0+0}{4+0}=\dfrac{1}{4}$