Question Number 36821 by Ajayraj1995 last updated on 06/Jun/18
$$>.\:\mathrm{2}{sin}\frac{\mathrm{5}\pi}{\mathrm{12}}{sin}\frac{\pi}{\mathrm{12}}\:{slove}\:{this}.? \\ $$
Commented bymaxmathsup by imad last updated on 06/Jun/18
$$=\mathrm{2}\:{sin}\left(\frac{\pi}{\mathrm{2}}\:−\frac{\pi}{\mathrm{12}}\right){sin}\left(\frac{\pi}{\mathrm{12}}\right)\:=\mathrm{2}{cos}\left(\frac{\pi}{\mathrm{12}}\right){sin}\left(\frac{\pi}{\mathrm{12}}\right)={sin}\left(\frac{\pi}{\mathrm{6}}\right)\:=\frac{\mathrm{1}}{\mathrm{2}}. \\ $$
Answered by tanmay.chaudhury50@gmail.com last updated on 06/Jun/18
$$={cos}\left(\frac{\mathrm{4}\Pi}{\mathrm{12}}\right)−{cos}\left(\frac{\mathrm{6}\Pi}{\mathrm{12}}\right) \\ $$ $$={cos}\left(\frac{\Pi}{\mathrm{3}}\right)−{cos}\left(\frac{\Pi}{\mathrm{2}}\right) \\ $$ $$=\frac{\mathrm{1}}{\mathrm{2}} \\ $$
Answered by Rio Mike last updated on 06/Jun/18
$$\mathrm{0}.\mathrm{5} \\ $$