Question Number 135389 by Bird last updated on 12/Mar/21
$${let}\:{U}_{{n}} =\int_{−\infty} ^{\infty} \:\:\frac{{cos}\left({nx}\right)}{\left({x}^{\mathrm{2}} −{x}+\mathrm{1}\right)^{\mathrm{2}} }{dx} \\ $$$${calculate}\:{lim}_{{n}\rightarrow\infty} {e}^{{n}^{\mathrm{2}} } {U}_{{n}} \\ $$