Giá trị lim (n^3−2n+1) bằng

Ta có:\[{n^3} - 2n + 1 = {n^3}\left( {1 - \frac{2}{{{n^2}}} + \frac{1}{{{n^3}}}} \right)\]

Vì\[\lim {n^3} = + \infty \] và\[\lim \left( {1 - \frac{2}{{{n^2}}} + \frac{1}{{{n^3}}}} \right) = 1 >0\] nên\[\lim \left( {{n^3} - 2n + 1} \right) = + \infty \]