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Category: Integration

0-sin-x-ln-x-x-dx-pi-2-

Question Number 99228 by  M±th+et+s last updated on 19/Jun/20 $$ \\ $$$$\int_{\mathrm{0}} ^{\infty} \frac{{sin}\left({x}\right){ln}\left({x}\right)}{{x}}{dx}=\frac{−\gamma\pi}{\mathrm{2}} \\ $$ Answered by maths mind last updated on 20/Jun/20 $$\frac{{ln}\left({x}\right)}{{x}}=\frac{\partial}{\partial{a}}{x}^{{a}−\mathrm{1}}…

x-x-3-1-dx-

Question Number 33689 by NECx last updated on 22/Apr/18 $$\int\frac{{x}}{{x}^{\mathrm{3}} +\mathrm{1}}{dx} \\ $$ Commented by mondodotto@gmail.com last updated on 22/Apr/18 $$\boldsymbol{\mathrm{let}}\:\boldsymbol{\mathrm{u}}=\boldsymbol{\mathrm{x}}^{\mathrm{3}} +\mathrm{1} \\ $$$$\frac{\boldsymbol{\mathrm{du}}}{\boldsymbol{\mathrm{dx}}}=\mathrm{3}\boldsymbol{\mathrm{x}}^{\mathrm{2}} \Rightarrow\boldsymbol{\mathrm{dx}}=\frac{\boldsymbol{\mathrm{du}}}{\mathrm{3}\boldsymbol{\mathrm{x}}^{\mathrm{2}}…

Question-99205

Question Number 99205 by bemath last updated on 19/Jun/20 Commented by bramlex last updated on 19/Jun/20 $${let}\:\sqrt{\mathrm{4}−\sqrt{{x}}}\:=\:{t}\:,\:\mathrm{4}−\sqrt{{x}}\:=\:{t}^{\mathrm{2}} \\ $$$$\left(\mathrm{4}−{t}^{\mathrm{2}} \right)^{\mathrm{2}} \:=\:{x}\:;\:{dx}\:=\:−\mathrm{4}{t}\left(\mathrm{4}−{t}^{\mathrm{2}} \right)\:{dt}\: \\ $$$$\mathrm{I}\:=\:\int\:{t}\:\left(−\mathrm{4}{t}\left(\mathrm{4}−{t}^{\mathrm{2}} \right)\right)\:{dt}\:…

Question-99173

Question Number 99173 by bemath last updated on 19/Jun/20 Answered by MJS last updated on 19/Jun/20 $$\mathrm{this}\:\mathrm{is}\:\mathrm{very}\:\mathrm{complicated} \\ $$$$\int\sqrt{\frac{\mathrm{1}+\mathrm{cot}\:{x}}{\mathrm{csc}\:{x}\:+\mathrm{cot}\:{x}}}{dx}=\int\sqrt{\frac{\mathrm{sin}\:{x}\:+\mathrm{cos}\:{x}}{\mathrm{1}+\mathrm{cos}\:{x}}}{dx}= \\ $$$$\:\:\:\:\:\left[{t}=\mathrm{tan}\:\frac{{x}}{\mathrm{2}}\:\rightarrow\:{dx}=\mathrm{2cos}^{\mathrm{2}} \:\frac{{x}}{\mathrm{2}}\:{dt}\right] \\ $$$$=\sqrt{\mathrm{2}}\int\frac{\sqrt{−{t}^{\mathrm{2}} +\mathrm{2}{t}+\mathrm{1}}}{{t}^{\mathrm{2}}…