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Category: Relation and Functions

let-A-n-0-e-nx-2-cos-x-2-dx-and-B-n-0-e-nx-2-sin-x-2-dx-n-N-1-calculate-A-n-and-B-n-2-find-lim-n-A-n-B-n-

Question Number 41513 by maxmathsup by imad last updated on 08/Aug/18 $${let}\:\:{A}_{{n}} =\:\int_{\mathrm{0}} ^{\infty} \:\:{e}^{−{nx}^{\mathrm{2}} } {cos}\left({x}^{\mathrm{2}} \right)\:{dx}\:\:{and}\:\:{B}_{{n}} =\int_{\mathrm{0}} ^{\infty} \:\:{e}^{−{nx}^{\mathrm{2}} } {sin}\left({x}^{\mathrm{2}} \right){dx}\:\:\:\:\left({n}\in\:{N}^{\bigstar} \right)…

let-A-n-0-ne-x-dx-with-n-2-1-calculate-A-n-2-find-nature-of-n-2-A-n-3-study-the-convergence-of-1-A-n-and-1-A-n-2-

Question Number 41410 by maxmathsup by imad last updated on 06/Aug/18 $${let}\:{A}_{{n}} =\int_{\mathrm{0}} ^{\infty} \:\:\left[{ne}^{−{x}} \right]{dx}\:\:{with}\:{n}\geqslant\mathrm{2} \\ $$$$\left.\mathrm{1}\right)\:{calculate}\:{A}_{{n}} \\ $$$$\left.\mathrm{2}\right)\:{find}\:{nature}\:{of}\:\sum_{{n}\geqslant\mathrm{2}} \:\:\:{A}_{{n}} \\ $$$$\left.\mathrm{3}\right)\:{study}\:{the}\:{convergence}\:{of}\:\:\Sigma\:\frac{\mathrm{1}}{{A}_{{n}} }\:\:{and}\:\Sigma\:\frac{\mathrm{1}}{{A}_{{n}} ^{\mathrm{2}}…

let-u-n-k-1-n-1-k-ln-n-1-prove-that-u-n-is-convergent-2-let-lim-n-u-n-prove-that-0-lt-lt-1-

Question Number 41345 by maxmathsup by imad last updated on 05/Aug/18 $${let}\:{u}_{{n}} =\:\sum_{{k}=\mathrm{1}} ^{{n}} \:\frac{\mathrm{1}}{{k}}\:−{ln}\left({n}\right) \\ $$$$\left.\mathrm{1}\right)\:{prove}\:{that}\:\left({u}_{{n}} \right){is}\:{convergent} \\ $$$$\left.\mathrm{2}\right)\:{let}\:\gamma\:={lim}_{{n}\rightarrow+\infty} {u}_{{n}} \:\:\:{prove}\:{that}\:\mathrm{0}<\gamma<\mathrm{1}\:\: \\ $$ Commented…