Question

tính \(lim\left[n\left(\sqrt{n^2+2}-\sqrt{n^2-4}\right)\right]\)

Answer 1

\(=\lim\limits\left[n\left(\dfrac{n^2+2-n^2+4}{\sqrt{n^2+2}+\sqrt{n^2-4}}\right)\right]=\lim\limits\dfrac{6n}{\sqrt{n^2+2}+\sqrt{n^2-4}}=\dfrac{6}{1+1}=3\)