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Author: Tinku Tara

0-1-x-1-x-2-dx-

Question Number 7585 by Tawakalitu. last updated on 04/Sep/16 $$\int_{\mathrm{0}} ^{\mathrm{1}} \frac{{x}}{\mathrm{1}\:+\:{x}^{\mathrm{2}} }\:{dx} \\ $$ Commented by sou1618 last updated on 05/Sep/16 $$\int_{\mathrm{0}} ^{\mathrm{1}} \frac{\mathrm{1}}{\mathrm{2}}×\frac{\mathrm{2}{x}}{{x}^{\mathrm{2}}…

Question-73117

Question Number 73117 by aliesam last updated on 06/Nov/19 Commented by mathmax by abdo last updated on 06/Nov/19 $${we}\:{have}\:{cos}\left(\mathrm{3}{x}\right)\sim\mathrm{1}−\frac{\left(\mathrm{3}{x}\right)^{\mathrm{2}} }{\mathrm{2}}\:\:\left({x}\rightarrow\mathrm{0}\right)\:\Rightarrow{cos}\left(\mathrm{3}{x}\right)−\mathrm{1}\:\sim−\frac{\mathrm{9}{x}^{\mathrm{2}} }{\mathrm{2}}\:\Rightarrow \\ $$$$\mathrm{1}−{cos}\left(\mathrm{3}{x}\right)\sim\frac{\mathrm{9}{x}^{\mathrm{2}} }{\mathrm{2}}\:\Rightarrow\frac{\mathrm{1}−{cos}\left(\mathrm{3}{x}\right)}{{x}^{\mathrm{2}} }\sim\frac{\mathrm{9}}{\mathrm{2}}\:\Rightarrow{lim}_{{x}\rightarrow\mathrm{0}}…

Question-73113

Question Number 73113 by TawaTawa last updated on 06/Nov/19 Commented by mathmax by abdo last updated on 06/Nov/19 $$\left.\mathrm{1}\right)\:{we}\:{have}\:{arg}\left({z}\right)={arg}\left(\mathrm{7}−\mathrm{3}\sqrt{\mathrm{3}}{i}\right)+{arg}\left(−\mathrm{1}−{i}\right)\left[\mathrm{2}\pi\right] \\ $$$$\mid\mathrm{7}−\mathrm{3}\sqrt{\mathrm{3}}\mid\:=\sqrt{\mathrm{49}+\mathrm{27}}=\sqrt{\mathrm{76}}\:\Rightarrow\mathrm{7}−\mathrm{3}\sqrt{\mathrm{3}}=\sqrt{\mathrm{76}}{e}^{{iarctan}\left(\frac{−\mathrm{3}\sqrt{\mathrm{3}}}{\mathrm{7}}\right)} \:\Rightarrow \\ $$$${arg}\left(\mathrm{7}−\mathrm{3}\sqrt{\mathrm{3}}\right)\:=−{arctan}\left(\frac{\mathrm{3}\sqrt{\mathrm{3}}}{\mathrm{7}}\right) \\…

Question-138641

Question Number 138641 by soudo last updated on 15/Apr/21 Answered by MJS_new last updated on 16/Apr/21 $$\left.\mathrm{f}\left.\mathrm{rom}\:\mathrm{1}\right)\:\Rightarrow\:\mathrm{2}\right) \\ $$$${x}^{\mathrm{2}} \pm{xy}+{y}^{\mathrm{2}} =\frac{\mathrm{1}}{\mathrm{2}}\left({x}^{\mathrm{2}} +{x}^{\mathrm{2}} \pm\mathrm{2}{xy}+{y}^{\mathrm{2}} +{y}^{\mathrm{2}} \right)=…