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Category: Integration

0-pi-x-sin-x-3-sin-2-x-dx-

Question Number 122979 by bemath last updated on 21/Nov/20 $$\:\:\int_{\mathrm{0}} ^{\pi} \frac{{x}\:\mathrm{sin}\:{x}}{\:\sqrt{\mathrm{3}+\mathrm{sin}\:^{\mathrm{2}} {x}}}\:{dx}\:? \\ $$ Answered by liberty last updated on 21/Nov/20 $$\psi\left({x}\right)=\int_{\mathrm{0}} ^{\pi} \frac{{x}\mathrm{sin}\:{x}}{\:\sqrt{\mathrm{4}−\mathrm{cos}\:^{\mathrm{2}}…

evaluate-0-pi-dx-a-bcosx-a-gt-0-and-deduce-that-0-pi-dx-a-bcos-x-2-pia-a-2-b-2-3-2-a-2-gt-b-2-and-0-pi-cos-x-dx-a-bcos-x-2-

Question Number 188511 by universe last updated on 02/Mar/23 $$\:\:\:{evaluate} \\ $$$$\int_{\mathrm{0}} ^{\pi} \frac{{dx}}{{a}+{b}\mathrm{cos}{x}\:}\:\:\:\:\:\:,\:\:\:{a}\:>\:\mathrm{0} \\ $$$$\:\:\:{and}\:{deduce}\:{that} \\ $$$$\:\:\:\int_{\mathrm{0}} ^{\pi} \frac{{dx}}{\left({a}+{b}\mathrm{cos}\:{x}\right)^{\mathrm{2}} }\:\:=\:\:\:\frac{\pi{a}}{\left({a}^{\mathrm{2}} −{b}^{\mathrm{2}} \right)^{\mathrm{3}/\mathrm{2}} }\:\:;\:\:{a}^{\mathrm{2}} >{b}^{\mathrm{2}}…

x-1-x-4-dx-

Question Number 122967 by bemath last updated on 21/Nov/20 $$\:\:\int\:\frac{{x}}{\:\sqrt{\mathrm{1}−{x}^{\mathrm{4}} }}\:{dx}\: \\ $$ Answered by bobhans last updated on 21/Nov/20 $${let}\:{x}^{\mathrm{2}} \:=\:\mathrm{sin}\:{t}\:\Rightarrow\:\mathrm{2}{x}\:{dx}\:=\:\mathrm{cos}\:{t}\:{dt} \\ $$$$\emptyset\left({x}\right)=\frac{\mathrm{1}}{\mathrm{2}}\int\:\frac{\mathrm{cos}\:{t}\:{dt}}{\:\sqrt{\mathrm{1}−\mathrm{sin}\:^{\mathrm{2}} {t}}}\:=\:\frac{\mathrm{1}}{\mathrm{2}}\int\:{dt}\:…