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Category: Integration

Question-128025

Question Number 128025 by Algoritm last updated on 03/Jan/21 Answered by Olaf last updated on 03/Jan/21 $$\mathrm{Let}\:\Phi_{{n}} \:=\:\int_{\mathrm{0}} ^{\mathrm{2}\pi} {e}^{\mathrm{cos}\theta} \mathrm{cos}\left({n}\theta−\mathrm{sin}\theta\right){d}\theta \\ $$$$\mathrm{Let}\:\Omega_{{n}} \:=\:\int_{\mathrm{0}} ^{\mathrm{2}\pi}…

nice-calculus-Titu-s-lemma-for-any-positive-numbers-a-1-a-2-a-n-b-1-b-2-b-n-we-have-a-1-a-n-2-b-1-b-n-a-1-2-b-1-a-n-2-

Question Number 128023 by mnjuly1970 last updated on 04/Jan/21 $$\:\:\:\:\:\:\:\:\:\:\:\:\:….{nice}\:\:{calculus}…= \\ $$$$\:\:{Titu}'{s}\:{lemma}:: \\ $$$$\:{for}\:{any}\:{positive}\:{numbers}\:: \\ $$$${a}_{\mathrm{1}} ,{a}_{\mathrm{2}} ,…,{a}_{{n}} \:,\:{b}_{\mathrm{1}} ,{b}_{\mathrm{2}} ,…,{b}_{{n}} \\ $$$$\:{we}\:{have}: \\ $$$$\:\frac{\left({a}_{\mathrm{1}}…

x-e-x-1-dx-for-x-gt-0-

Question Number 62453 by Tawa1 last updated on 21/Jun/19 $$\int\:\frac{\mathrm{x}}{\mathrm{e}^{\mathrm{x}} \:−\:\mathrm{1}}\mathrm{dx},\:\:\:\:\:\:\:\:\:\:\:\:\mathrm{for}\:\:\mathrm{x}\:>\:\mathrm{0} \\ $$ Commented by mathmax by abdo last updated on 21/Jun/19 $$\int\:\:\frac{{x}}{{e}^{{x}} −\mathrm{1}}{dx}\:=\int\:\:\frac{{x}\:{e}^{−{x}} }{\mathrm{1}−{e}^{−{x}}…

let-f-x-0-1-arctan-1-xt-t-2-1-dt-determine-a-explicit-form-for-f-x-2-calculate-0-1-arctan-1-2t-1-t-2-dt-

Question Number 62437 by mathsolverby Abdo last updated on 21/Jun/19 $${let}\:{f}\left({x}\right)\:=\int_{\mathrm{0}} ^{\mathrm{1}} \:\frac{{arctan}\left(\mathrm{1}+{xt}\right)}{{t}^{\mathrm{2}} \:+\mathrm{1}}{dt} \\ $$$${determine}\:{a}\:{explicit}\:{form}\:{for}\:{f}\left({x}\right) \\ $$$$\left.\mathrm{2}\right){calculate}\:\int_{\mathrm{0}} ^{\mathrm{1}} \:\frac{{arctan}\left(\mathrm{1}+\mathrm{2}{t}\right)}{\mathrm{1}+{t}^{\mathrm{2}} }{dt} \\ $$$$ \\ $$…

let-x-n-1-1-n-x-with-x-gt-1-1-calculate-lim-x-1-x-and-lim-x-x-2-prove-that-x-1-2-x-o-2-x-x-3-prove-that-is-decreasing-and-convexe-fuc

Question Number 62425 by mathmax by abdo last updated on 21/Jun/19 $${let}\:\xi\left({x}\right)\:=\sum_{{n}=\mathrm{1}} ^{\infty} \:\frac{\mathrm{1}}{{n}^{{x}} }\:\:\:\:\:{with}\:{x}>\mathrm{1} \\ $$$$\left.\mathrm{1}\right)\:{calculate}\:{lim}_{{x}\rightarrow\mathrm{1}^{+} } \:\:\xi\left({x}\right)\:\:{and}\:{lim}_{{x}\rightarrow+\infty} \:\:\:\xi\left({x}\right) \\ $$$$\left.\mathrm{2}\right)\:{prove}\:{that}\:\xi\left({x}\right)\:=\mathrm{1}+\mathrm{2}^{−{x}} \:+{o}\left(\mathrm{2}^{−{x}} \right)\:\:\:\left({x}\rightarrow+\infty\right) \\…

let-u-n-x-1-n-x-n-n-1-dt-t-x-with-x-1-2-1-prove-that-0-u-n-x-1-n-x-1-n-1-x-n-gt-0-2-prove-that-u-n-x-converges-let-n-1-u-n-1-3-find-n-1-u-n-x-i

Question Number 62420 by mathsolverby Abdo last updated on 20/Jun/19 $${let}\:{u}_{{n}} \left({x}\right)=\frac{\mathrm{1}}{{n}^{{x}} }\:−\int_{{n}} ^{{n}+\mathrm{1}} \frac{{dt}}{{t}^{{x}} }\:\:{with}\:{x}\in\left[\mathrm{1},\mathrm{2}\right] \\ $$$$\left.\mathrm{1}\right){prove}\:{that}\:\mathrm{0}\leqslant\:{u}_{{n}} \left({x}\right)\leqslant\frac{\mathrm{1}}{{n}^{{x}} }−\frac{\mathrm{1}}{\left({n}+\mathrm{1}\right)^{{x}} }\:\left({n}>\mathrm{0}\right) \\ $$$$\left.\mathrm{2}\right){prove}\:{that}\:\Sigma\:{u}_{{n}} \left({x}\right){converges} \\…