Tính lim (n^3 + 4n - 5) / (3n^3 + n^2 + 7)
Câu hỏi:
Tính \(\lim \frac{{{n^3} + 4n - 5}}{{3{n^3} + {n^2} + 7}}\).
Trả lời:
\(\lim \frac{{{n^3} + 4n - 5}}{{3{n^3} + {n^2} + 7}}\)
\( = \lim \frac{{1 + \frac{4}{{{n^2}}} - \frac{5}{{{n^3}}}}}{{3 + \frac{1}{n} + \frac{7}{{{n^3}}}}}\)
\( = \frac{{1 + 0 - 0}}{{3 + 0 + 0}} = \frac{1}{3}\).