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Category: Integration

calculate-dx-cosx-cos-2x-cos-3x-

Question Number 84577 by msup trace by abdo last updated on 14/Mar/20 $${calculate}\:\int\:\:\:\:\frac{{dx}}{{cosx}\:+{cos}\left(\mathrm{2}{x}\right)+{cos}\left(\mathrm{3}{x}\right)} \\ $$ Commented by jagoll last updated on 14/Mar/20 $$\mathrm{cos}\:{x}+\mathrm{cos}\:\mathrm{3}{x}+\mathrm{cos}\:\mathrm{2}{x}\:=\: \\ $$$$\mathrm{2cos}\:\mathrm{2}{x}\:\mathrm{cos}\:{x}\:+\:\mathrm{cos}\:\mathrm{2}{x}\:=\:…

Question-84557

Question Number 84557 by Power last updated on 14/Mar/20 Commented by jagoll last updated on 14/Mar/20 $$\mathrm{ln}\left(\mathrm{cos}\:\mathrm{x}\right)\:=\:\mathrm{u}\:\Rightarrow\:\mathrm{cos}\:\mathrm{x}\:=\:\mathrm{e}^{\mathrm{u}} \\ $$$$−\mathrm{sin}\:\mathrm{x}\:\mathrm{dx}\:=\:\mathrm{e}^{\mathrm{u}} \:\mathrm{du}\: \\ $$$$\mathrm{dx}\:=\:\frac{−\mathrm{e}^{\mathrm{u}} }{\mathrm{sin}\:\mathrm{x}}\:\mathrm{dx}\:=\:\frac{−\mathrm{e}^{\mathrm{u}} \:\mathrm{du}}{\:\sqrt{\mathrm{1}−\mathrm{e}^{\mathrm{2u}} }}…

sin-1-2x-2-4x-2-8x-13-dx-

Question Number 84556 by jagoll last updated on 14/Mar/20 $$\int\:\mathrm{sin}^{−\mathrm{1}} \left(\frac{\mathrm{2x}+\mathrm{2}}{\:\sqrt{\mathrm{4x}^{\mathrm{2}} +\mathrm{8x}+\mathrm{13}}}\right)\:\mathrm{dx} \\ $$ Commented by john santu last updated on 14/Mar/20 $$\int\:\mathrm{sin}^{−\mathrm{1}} \left(\frac{\mathrm{2x}+\mathrm{2}}{\:\sqrt{\left(\mathrm{2x}+\mathrm{2}\right)^{\mathrm{2}} +\mathrm{9}}}\right)\:\mathrm{dx}…