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Category: Integration

I-1-x-4-1-dx-

Question Number 86703 by lémùst last updated on 30/Mar/20 $${I}=\int\frac{\mathrm{1}}{{x}^{\mathrm{4}} +\mathrm{1}}{dx} \\ $$ Commented by john santu last updated on 30/Mar/20 $$\mathrm{x}^{\mathrm{4}} +\mathrm{1}\:=\:\left(\mathrm{x}^{\mathrm{2}} −\mathrm{i}\right)\left(\mathrm{x}^{\mathrm{2}} +\mathrm{i}\right)…

sin-x-arcsin-x-

Question Number 86671 by M±th+et£s last updated on 30/Mar/20 $$\int{sin}\left({x}\right)\:{arcsin}\left({x}\right) \\ $$ Answered by Rio Michael last updated on 30/Mar/20 $$\mathrm{let}\:\mathrm{me}\:\mathrm{give}\:\mathrm{a}\:\mathrm{try}. \\ $$$$\:\int\:\mathrm{sin}\:\left({x}\right)\:\mathrm{arcsin}\left({x}\right)\:{dx} \\ $$$$\mathrm{using}\:\mathrm{the}\:\mathrm{taylor}\:\mathrm{series}\:\mathrm{expansion}\:\mathrm{for}\:\mathrm{sin}\:\left({x}\right)\:\mathrm{arcsin}\:\left({x}\right)\:\mathrm{centred}\:\mathrm{at}\:\mathrm{0}…

If-x-is-real-show-that-2-i-1-3i-x-2-i-1-3i-x-is-also-real-

Question Number 152203 by peter frank last updated on 26/Aug/21 $$\mathrm{If}\:\mathrm{x}\:\mathrm{is}\:\mathrm{real}\:\mathrm{show}\:\mathrm{that} \\ $$$$\left(\mathrm{2}+\mathrm{i}\right)^{\left(\mathrm{1}+\mathrm{3i}\right)\mathrm{x}} +\left(\mathrm{2}−\mathrm{i}\right)^{\left(\mathrm{1}−\mathrm{3i}\right)\mathrm{x}} \\ $$$$\mathrm{is}\:\mathrm{also}\:\mathrm{real} \\ $$ Commented by MJS_new last updated on 26/Aug/21…

Integral-I-0-pi-ln-sin-x-tan-1-cot-x-dx-0-proof-I-0-pi-ln-sin-x-tan-1-tan-pi-2-x-dx-0-pi-pi-2-x-

Question Number 152201 by mnjuly1970 last updated on 26/Aug/21 $$ \\ $$$$\:\:\:…\mathrm{Integral}… \\ $$$$\:\:\:\:\:\:\:\:\:\:\mathrm{I}\::=\:\int_{\mathrm{0}} ^{\:\pi} {ln}\:\left({sin}\left({x}\right)\:\right).{tan}^{\:−\mathrm{1}} \left({cot}\left({x}\right)\right){dx}\overset{?} {=}\:\mathrm{0} \\ $$$$\:\:\:\:\:{proof}\:::\:…. \\ $$$$\:\:\:\:\:\:\mathrm{I}\::=\:\int_{\mathrm{0}} ^{\:\pi} {ln}\:\left({sin}\left({x}\right)\:\right).\:{tan}^{\:−\mathrm{1}} \left(\:{tan}\left(\frac{\pi}{\mathrm{2}}\:−{x}\:\right)\right){dx}…

x-n-cos-nx-dx-

Question Number 152186 by Tawa11 last updated on 26/Aug/21 $$\int\mathrm{x}^{\mathrm{n}} \:\mathrm{cos}\left(\mathrm{nx}\right)\:\mathrm{dx} \\ $$ Answered by mindispower last updated on 26/Aug/21 $${nx}={y} \\ $$$$\Leftrightarrow\frac{\mathrm{1}}{{n}^{{n}+\mathrm{1}} }\int{y}^{{n}} {cos}\left({x}\right){dx}…

sin-x-sin-3x-dx-

Question Number 152165 by peter frank last updated on 26/Aug/21 $$\int\frac{\mathrm{sin}\:\mathrm{x}}{\mathrm{sin}\:\mathrm{3x}}\mathrm{dx} \\ $$ Answered by john_santu last updated on 26/Aug/21 $$\:\mathrm{I}=\int\:\frac{\mathrm{sin}\:\mathrm{x}}{\mathrm{3sin}\:\mathrm{x}−\mathrm{4sin}\:^{\mathrm{3}} \mathrm{x}}\:\mathrm{dx}\: \\ $$$$\mathrm{I}=\int\:\frac{\mathrm{dx}}{\mathrm{3}−\mathrm{4sin}\:^{\mathrm{2}} \mathrm{x}}…