\(\lim\left(2n^3-100n+9\right)=\lim n^3\left(2-\dfrac{100}{n^2}+\dfrac{9}{n^3}\right)=+\infty.2=+\infty\)
\(\lim\sqrt{2n^4-n^2+n+2}=\lim n^2\sqrt{2-\dfrac{1}{n^2}+\dfrac{1}{n^3}+\dfrac{2}{n^4}}=+\infty.\sqrt{2}=+\infty\)
\(\lim\sqrt[3]{1+2n-n^3}=\lim n\sqrt[3]{\dfrac{1}{n^3}+\dfrac{2}{n^2}-1}=+\infty.\left(-1\right)=-\infty\)