Question Number 61721 by Mr X pcx last updated on 07/Jun/19
$${calculate}\:{A}\:=\int_{\mathrm{0}} ^{\infty} \:{cos}\left({x}^{{n}} \right){dx} \\ $$$${and}\:{B}\:=\int_{\mathrm{0}} ^{\infty} \:{sin}\left({x}^{{n}} \right){dx}\:\:{with} \\ $$$${n}\geqslant\mathrm{2}\:\:\left({n}\:{integr}\:{natural}\right) \\ $$