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Category: Integration

let-f-n-x-sin-2-n-1-x-sinx-if-x-0-pi-2-and-f-n-0-2-n-1-let-u-n-0-pi-2-f-n-x-dx-1-prove-that-n-fromN-u-n-1-u-n-2-1-n-1-2n-3-2-find-lim-n-u-n-

Question Number 41515 by maxmathsup by imad last updated on 08/Aug/18 $$\left.{l}\left.{et}\:\:{f}_{{n}} \left({x}\right)\:=\frac{{sin}\left(\mathrm{2}\left({n}+\mathrm{1}\right){x}\right)}{{sinx}}\:{if}\:\:{x}\in\right]\mathrm{0},\frac{\pi}{\mathrm{2}}\right]\:{and}\:{f}_{{n}} \left(\mathrm{0}\right)=\mathrm{2}\left({n}+\mathrm{1}\right)\:\:{let} \\ $$$${u}_{{n}} =\:\int_{\mathrm{0}} ^{\frac{\pi}{\mathrm{2}}} \:{f}_{{n}} \left({x}\right){dx} \\ $$$$\left.\mathrm{1}\right)\:{prove}\:{that}\:\:\forall{n}\:{fromN}\:\:{u}_{{n}+\mathrm{1}} −{u}_{{n}} =\mathrm{2}\frac{\left(−\mathrm{1}\right)^{{n}+\mathrm{1}} }{\mathrm{2}{n}+\mathrm{3}}…

find-cos-lnx-dx-

Question Number 41514 by maxmathsup by imad last updated on 08/Aug/18 $${find}\:\:\:\int\:\:{cos}\left({lnx}\right){dx}\: \\ $$ Answered by alex041103 last updated on 09/Aug/18 $${We}\:{know}\:{that}\:{cos}\left(\theta\right)={Re}\left({e}^{{i}\theta} \right) \\ $$$${We}\:{will}\:{assume}\:{x}\epsilon\mathbb{R}.…

1-x-2-dx-x-4-

Question Number 107036 by john santu last updated on 08/Aug/20 $$\int\:\frac{\sqrt{\mathrm{1}+\mathrm{x}^{\mathrm{2}} }\:\mathrm{dx}}{\mathrm{x}^{\mathrm{4}} }\:? \\ $$ Commented by kaivan.ahmadi last updated on 08/Aug/20 $${x}={tgu}\Rightarrow{dx}=\left(\mathrm{1}+{tg}^{\mathrm{2}} {u}\right){du}={sec}^{\mathrm{2}} {udu}…

find-0-1-x-1-x-lnx-dx-

Question Number 172564 by Mathspace last updated on 28/Jun/22 $${find}\:\int_{\mathrm{0}} ^{\mathrm{1}} \sqrt{{x}}\sqrt{\mathrm{1}−\sqrt{{x}}}{lnx}\:{dx} \\ $$ Answered by Ar Brandon last updated on 28/Jun/22 $${I}=\int_{\mathrm{0}} ^{\mathrm{1}} \sqrt{{x}}\sqrt{\mathrm{1}−\sqrt{{x}}}\mathrm{ln}{xdx},\:{x}={t}^{\mathrm{2}}…

Question-41487

Question Number 41487 by behi83417@gmail.com last updated on 08/Aug/18 Commented by maxmathsup by imad last updated on 08/Aug/18 $$\left.\mathrm{2}\right)\:{we}\:{have}\:{I}\:=\:\int\:\:\:\:\:\:\:\frac{{dx}}{\left(\mathrm{1}+{x}\right)\sqrt{\left({x}+\frac{\mathrm{1}}{\mathrm{2}}\right)^{\mathrm{2}} +\frac{\mathrm{3}}{\mathrm{4}}}}\:\:{changement}\:{x}+\frac{\mathrm{1}}{\mathrm{2}}\:=\frac{\sqrt{\mathrm{3}}}{\mathrm{2}}{sh}\left({t}\right)\:{give} \\ $$$${I}\:=\:\int\:\:\:\:\:\:\frac{\mathrm{1}}{\left(\mathrm{1}+\frac{\sqrt{\mathrm{3}}}{\mathrm{2}}{sh}\left({t}\right)−\frac{\mathrm{1}}{\mathrm{2}}\right)\frac{\sqrt{\mathrm{3}}}{\mathrm{2}}{ch}\left({t}\right)}\frac{\sqrt{\mathrm{3}}}{\mathrm{2}}{ch}\left({t}\right){dt} \\ $$$$=\int\:\:\:\:\:\:\:\:\:\:\:\frac{{dt}}{\frac{\mathrm{1}}{\mathrm{2}}\:+\frac{\sqrt{\mathrm{3}}}{\mathrm{2}}{sh}\left({t}\right)}\:=\:\int\:\:\:\frac{\mathrm{2}{dt}}{\:\sqrt{\mathrm{3}}\frac{{e}^{{t}} −{e}^{−{t}}…

1-5-5-arctan-x-x-dx-

Question Number 172555 by cortano1 last updated on 28/Jun/22 $$\:\:\:\:\:\:\underset{\mathrm{1}/\mathrm{5}} {\overset{\mathrm{5}} {\int}}\:\frac{\mathrm{arctan}\:\left({x}\right)}{{x}}\:{dx}\:=? \\ $$ Commented by greougoury555 last updated on 28/Jun/22 $$\:=\:\mathrm{ln}\:\sqrt{\mathrm{5}^{\pi} }\:=\:\frac{\pi}{\mathrm{2}}\:\mathrm{ln}\:\mathrm{5} \\ $$…