calculus - Find $lim_{nrightarrowinfty}sqrt{n}int_{-infty}^{+infty}frac{cos(x)}{(1+x^2)^{n}}dx$?

I don't know from which point I have to start finding this limit $$\lim_{n\rightarrow\infty}\sqrt{n}\int_{-\infty}^{+\infty}\frac{\cos(x)}{(1+x^2)^{n}}dx$$