Question Number 61056 by Tawa1 last updated on 28/May/19
$$\int\:\frac{\mathrm{x}\:+\:\mathrm{sin}\left(\mathrm{x}\right)}{\mathrm{1}\:+\:\mathrm{cos}\left(\mathrm{x}\right)}\:\mathrm{dx} \\ $$
Answered by perlman last updated on 28/May/19
$${cos}\left({x}\right)=\mathrm{2}{cos}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right)−\mathrm{1} \\ $$$$\frac{{x}+{sin}\left({x}\right)}{\mathrm{1}+{cos}\left({x}\right)}=\frac{{x}+{sin}\left({x}\right)}{\mathrm{2}{cos}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right)}=\frac{{x}}{\mathrm{2}{cos}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right)}+\frac{\mathrm{2}{sin}\left(\frac{{x}}{\mathrm{2}}\right){cos}\left(\frac{{x}}{\mathrm{2}}\right)}{\mathrm{2}{cos}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right)} \\ $$$$=\frac{{x}}{\mathrm{2}}\left(\mathrm{1}+{tan}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right)\right)+\frac{{sin}\left(\frac{{x}}{\mathrm{2}}\right)}{{cos}\left(\frac{{x}}{\mathrm{2}}\right)} \\ $$$$==>\int\frac{{x}+{sin}\left({x}\right)}{\mathrm{1}+{cos}\left({x}\right)}{dx}=\int\frac{{x}}{\mathrm{2}}\left(\mathrm{1}+{tg}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right)\right){dx}+\int\frac{{sin}\left(\frac{{x}}{\mathrm{2}}\right)}{{cos}\left(\frac{{x}}{\mathrm{2}}\right)}{dx} \\ $$$$\int\frac{{sin}\left(\frac{{x}}{\mathrm{2}}\right)}{{cos}\left(\frac{{x}}{\mathrm{2}}\right)}{dx}=−\mathrm{2}{ln}\mid{cos}\left(\frac{{x}}{\mathrm{2}}\right)\mid \\ $$$$\int\frac{{x}}{\mathrm{2}}\left(\mathrm{1}+{tan}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right)\right){dx}={xtan}\left(\frac{{x}}{\mathrm{2}}\right)−\int{tan}\left(\frac{{x}}{\mathrm{2}}\right){dx}={xtan}\left(\frac{{x}}{\mathrm{2}}\right)+\mathrm{2}{ln}\mid{cos}\left(\frac{{x}}{\mathrm{2}}\right)\mid+{c} \\ $$$$\int\frac{{x}+{sin}\left({x}\right)}{{cos}\left({x}\right)+\mathrm{1}}{dx}={xtan}\left(\frac{{x}}{\mathrm{2}}\right)+{c}\:\:\:\:\:\:\:{c}\:{constant}…. \\ $$$$ \\ $$
Commented by Tawa1 last updated on 28/May/19
$$\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir} \\ $$
Answered by perlman last updated on 28/May/19
$$\mathrm{2}\:{nd} \\ $$$${x}+{sin}\left({x}\right)={x}\left({cos}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right)+{sin}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right)\right)+\mathrm{2}{sin}\left(\frac{{x}}{\mathrm{2}}\right){cos}\left(\frac{{x}}{\mathrm{2}}\right) \\ $$$$\mathrm{1}+{cos}\left({x}\right)=\mathrm{2}{cos}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right) \\ $$$$\int\:\frac{\mathrm{x}\:+\:\mathrm{sin}\left(\mathrm{x}\right)}{\mathrm{1}\:+\:\mathrm{cos}\left(\mathrm{x}\right)}\:\mathrm{dx}=\int\frac{{x}}{\mathrm{2}}\left(\mathrm{1}+{tan}^{\mathrm{2}} \left(\frac{{x}}{\mathrm{2}}\right)\right)+{tg}\left(\frac{{x}}{\mathrm{2}}\right){dx}=\int{d}\left({xtan}\left(\frac{{x}}{\mathrm{2}}\right)\right)={xtan}\left(\frac{{x}}{\mathrm{2}}\right)+{c} \\ $$$$ \\ $$
Commented by Tawa1 last updated on 28/May/19
$$\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir} \\ $$