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Category: Integration

Question-81921

Question Number 81921 by M±th+et£s last updated on 16/Feb/20 Answered by MJS last updated on 16/Feb/20 $$\int\frac{\sqrt{\sqrt{{x}}+\sqrt{{x}−\mathrm{1}}}}{\:\sqrt{{x}}+\mathrm{1}}{dx}= \\ $$$$\:\:\:\:\:\left[{t}=\sqrt{{x}}+\sqrt{{x}−\mathrm{1}}\:\rightarrow\:{dx}=\frac{{t}^{\mathrm{4}} −\mathrm{1}}{\mathrm{2}{t}^{\mathrm{3}} }{dt}\right] \\ $$$$=\int\frac{\left({t}−\mathrm{1}\right)\left({t}^{\mathrm{2}} +\mathrm{1}\right)}{\:\sqrt{{t}^{\mathrm{3}} }\left({t}+\mathrm{1}\right)}{dt}=…

Question-81889

Question Number 81889 by rajesh4661kumar@gmail.com last updated on 16/Feb/20 Answered by john santu last updated on 16/Feb/20 $${let}\:\sqrt{{x}}\:=\:\mathrm{sin}\:{t}\:\Rightarrow{x}\:=\:\mathrm{sin}\:^{\mathrm{2}} {t} \\ $$$${dx}\:=\:\mathrm{2sin}\:{t}\:\mathrm{cos}\:{t}\:{dt}\: \\ $$$$\Rightarrow{I}\:=\:\int\:\sqrt{\frac{\mathrm{1}−\mathrm{sin}\:{t}}{\mathrm{1}+\mathrm{sin}\:{t}}\:}\:\left(\mathrm{2sin}\:{t}\:\mathrm{cos}\:{t}\:\right)\:{dt} \\ $$$$=\:\int\:\frac{\left(\mathrm{1}−\mathrm{sin}\:{t}\right)\mathrm{2sin}\:{t}\mathrm{cos}\:{t}}{\mathrm{cos}\:{t}}\:{dt}…

Question-81888

Question Number 81888 by rajesh4661kumar@gmail.com last updated on 16/Feb/20 Commented by mathmax by abdo last updated on 16/Feb/20 $${let}\:{A}\:=\int\:\:\frac{{dx}}{\left({x}^{\mathrm{2}} +\mathrm{1}\right)\sqrt{{x}^{\mathrm{2}} −\mathrm{1}}}\:\:{we}\:{do}\:{the}\:{changement}\:{x}\:={cht}\:\Rightarrow \\ $$$${A}\:=\int\:\:\:\frac{{sht}\:{dt}}{\left({ch}^{\mathrm{2}} {t}\:+\mathrm{1}\right){sht}}\:=\int\:\:\frac{{dt}}{\mathrm{1}+\frac{\mathrm{1}+{ch}\left(\mathrm{2}{t}\right)}{\mathrm{2}}}\:=\int\:\:\frac{\mathrm{2}{dt}}{\mathrm{3}+{ch}\left(\mathrm{2}{t}\right)} \\…

Question-81801

Question Number 81801 by Power last updated on 15/Feb/20 Commented by mathmax by abdo last updated on 16/Feb/20 $${changement}\:{x}^{{n}} \:={cos}^{\mathrm{2}} {t}\:{give}\:{x}\:=\left({cost}\right)^{\frac{\mathrm{2}}{{n}}} \:\Rightarrow{dx}\:=−\frac{\mathrm{2}}{{n}}{sint}\:\left({cost}\right)^{\frac{\mathrm{2}}{{n}}−\mathrm{1}} \\ $$$$\Rightarrow\int_{\mathrm{0}} ^{\mathrm{1}}…

Question-147309

Question Number 147309 by puissant last updated on 19/Jul/21 Answered by mathmax by abdo last updated on 19/Jul/21 $$\mathrm{I}=\int_{\mathrm{0}} ^{\infty} \:\frac{\mathrm{cosx}}{\left(\mathrm{x}^{\mathrm{2}} \:+\mathrm{1}\right)^{\mathrm{2}} }\:\Rightarrow\mathrm{2I}=\int_{−\infty} ^{+\infty} \:\frac{\mathrm{cosx}}{\left(\mathrm{x}^{\mathrm{2}}…

Advanced-Calculus-Calculate-i-I-0-1-ln-x-ln-1-x-dx-ii-J-0-1-Li-2-1-x-2-Note-Li-2-x-

Question Number 147287 by mnjuly1970 last updated on 19/Jul/21 $$ \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:…\mathrm{Advanced}\:\:\mathrm{Calculus}… \\ $$$$ \\ $$$$\:\:\:\:\:\:\mathrm{C}{alculate}\:::\:\:\:\:\begin{cases}{\:\:\mathrm{i}\:::\:\:\:\:\:\:\mathrm{I}\::=\:\int_{\mathrm{0}} ^{\:\mathrm{1}} \mathrm{ln}\left(\mathrm{x}\right).\mathrm{ln}\left(\mathrm{1}+\mathrm{x}\right)\:\mathrm{dx}}\\{\:\:\mathrm{ii}\:::\:\:\:\:\:\mathrm{J}\::=\:\int_{\mathrm{0}} ^{\:\mathrm{1}} \mathrm{Li}_{\:\mathrm{2}} \left(\:\mathrm{1}−\:\mathrm{x}^{\:\mathrm{2}} \right)\:=?}\end{cases} \\ $$$$\:\:\:\:\:\:\:\:\:\:\mathrm{Note}::\:\:\:\mathrm{Li}_{\mathrm{2}} \:\left(\mathrm{x}\right)\:=\:\underset{{n}=\mathrm{1}}…