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Category: Integration

nice-calculus-prove-that-I-0-pi-2-cot-x-cot-x-dx-1-2-pi-ln-sinh-pi-pi-x-is-fractional-part-of-x-

Question Number 126986 by mnjuly1970 last updated on 25/Dec/20 $$\:\:\:\:\:\:\:\:\:\:\:…\:{nice}\:\:{calculus}… \\ $$$$\:\:\:\:\:{prove}\:\:{that}\::: \\ $$$$\:\:\:\:\mathrm{I}\::=\:\int_{\mathrm{0}} ^{\:\frac{\pi}{\mathrm{2}}} \frac{\left\{{cot}\left({x}\right)\right\}}{{cot}\left({x}\right)}{dx}=\frac{\mathrm{1}}{\mathrm{2}}\left(\pi−{ln}\left(\frac{{sinh}\left(\pi\right)}{\pi}\right)\right) \\ $$$$\left\{{x}\right\}\:{is}\:{fractional}\:{part}\:{of}\:\:{x}\:.. \\ $$ Answered by Olaf last updated…

Question-192470

Question Number 192470 by Spillover last updated on 19/May/23 Answered by Spillover last updated on 19/May/23 $$\int_{\mathrm{0}} ^{\sqrt{\mathrm{2}}} \sqrt{\mathrm{1}+\left(\mathrm{2}{x}\right)^{\mathrm{2}} }\:{dx} \\ $$$${Let}\:\:\:\mathrm{2}{x}=\mathrm{sinh}\:\theta\:\:\:\:\:\:\:\:\:\:\:{dx}=\:\frac{\mathrm{cosh}\:\theta{d}\theta}{\mathrm{2}} \\ $$$$\int_{\mathrm{0}} ^{\sqrt{\mathrm{2}}}…

Question-61349

Question Number 61349 by tanmay last updated on 01/Jun/19 Commented by MJS last updated on 01/Jun/19 $$…\mathrm{harder}\:\mathrm{than}\:\mathrm{I}\:\mathrm{thought} \\ $$$$\int\frac{\sqrt{{t}^{\mathrm{2}} −\mathrm{5}}}{{t}−{a}}{dt}= \\ $$$$\:\:\:\:\left[{t}=\frac{\sqrt{\mathrm{5}}}{\mathrm{sin}\:{u}}\:\Leftrightarrow\:{u}=\mathrm{arcsin}\:\frac{\sqrt{\mathrm{5}}}{{t}}\:\rightarrow\:{dt}=−\frac{{t}\sqrt{{t}^{\mathrm{2}} −\mathrm{5}}}{\:\sqrt{\mathrm{5}}}{du}\right] \\ $$$$\:\:\:\:\:\mathrm{now}\:\mathrm{the}\:\mathrm{root}\:\mathrm{is}\:\mathrm{gone},\:\mathrm{but}\:\mathrm{we}\:\mathrm{must}\:\mathrm{make}…

x-4-1-x-8-dx-

Question Number 126879 by bramlexs22 last updated on 25/Dec/20 $$\:\int\:\frac{{x}^{\mathrm{4}} }{\mathrm{1}+{x}^{\mathrm{8}} }\:{dx}\:? \\ $$ Answered by Lordose last updated on 25/Dec/20 $$\Omega\:=\:\int^{\:} \frac{\mathrm{x}^{\mathrm{4}} }{\mathrm{1}+\mathrm{x}^{\mathrm{8}} }\mathrm{dx}\:=\:\underset{\mathrm{n}=\mathrm{0}}…