Tìm các giới hạn sau:

a) \(lim\sqrt[3]{-n^3+2n^2-5}\)

b) \(lim\dfrac{1}{\sqrt{n+1}-\sqrt{n}}\)

c) \(lim\left(\dfrac{1}{n+1}-n\right)\)

d) \(lim\left(\dfrac{2n^2-1}{n+1}-2n\right)\)

e) \(lim\dfrac{2n^3+n^2-3n+1}{2-3n}\)

Tìm các giới hạn sau:

a) \(lim\left(\sqrt{4n+1}-2\sqrt{n}\right)\)

b) \(lim\left(\sqrt{n^2+2n}-\sqrt{n^2-2n}-n\right)\)

c) \(lim\left(\sqrt{9^n-3^n}-4^n\right)\)

d) \(lim\left(3n^3+2n^2+n\right)\)

tìm \(lim\left(-n^4-50n+11\right)\)

tìm \(lim\left(3n^4+29n^2-3n-1\right)\)