Question Number 95326 by bobhans last updated on 24/May/20 $$\mathrm{sin}\:\mathrm{72}^{\mathrm{o}} \:=\:\mathrm{p}\sqrt{\mathrm{3}}\:\mathrm{cos}\:\mathrm{48}^{\mathrm{o}} \\ $$$$\mathrm{find}\:\mathrm{tan}\:\mathrm{12}^{\mathrm{o}} \:? \\ $$ Commented by mr W last updated on 24/May/20 $$\mathrm{sin}\:\mathrm{72}°=\mathrm{sin}\:\left(\mathrm{60}°+\mathrm{12}°\right)=\frac{\mathrm{1}}{\mathrm{2}}\left(\sqrt{\mathrm{3}}\mathrm{cos}\:\mathrm{12}°+\mathrm{sin}\:\mathrm{12}°\right)…
Question Number 160815 by cortano last updated on 07/Dec/21 $$\:\:\:\:\mathrm{sec}\:\left(\mathrm{3x}\right)−\mathrm{6cos}\:\left(\mathrm{3x}\right)=\mathrm{4sin}\:\left(\mathrm{3x}\right) \\ $$$$\:\:\:\:\mathrm{find}\:\mathrm{the}\:\mathrm{solution} \\ $$ Commented by blackmamba last updated on 07/Dec/21 $$\:\Rightarrow\frac{\mathrm{1}}{\mathrm{cos}\:\mathrm{3}{x}}\:−\mathrm{6cos}\:\mathrm{3}{x}\:=\:\mathrm{4sin}\:\mathrm{3}{x}\: \\ $$$$\Rightarrow\frac{\mathrm{1}}{{t}}\:−\:\mathrm{6}{t}\:=\:\mathrm{4}\sqrt{\mathrm{1}−{t}^{\mathrm{2}} }\:;\:\left[\:{t}\:=\:\mathrm{cos}\:\mathrm{3}{x}\:\right]…
Question Number 160762 by mathlove last updated on 06/Dec/21 $$\mathrm{sin}\:\mathrm{10}+\mathrm{sin}\:\mathrm{20}+\mathrm{sin}\:\mathrm{30}+\mathrm{sin}\:\mathrm{40}+\centerdot\centerdot\centerdot\centerdot+\mathrm{sin}\:\mathrm{360}=? \\ $$ Commented by som(math1967) last updated on 06/Dec/21 $$\mathrm{0} \\ $$ Commented by mathlove…
Question Number 29658 by gyugfeet last updated on 11/Feb/18 $${tan}\theta+{tan}\mathrm{2}\theta+\sqrt{\mathrm{3}}\:{tan}\theta.{tan}\mathrm{2}\theta=\sqrt{\mathrm{3}}\:\:\:\:\:\left(\mathrm{0}^{{o}\:} \leqslant\theta\leqslant\mathrm{360}\right) \\ $$ Answered by mrW2 last updated on 11/Feb/18 $${tan}\theta+{tan}\mathrm{2}\theta=\sqrt{\mathrm{3}}\left(\mathrm{1}−\:{tan}\theta.{tan}\mathrm{2}\theta\right) \\ $$$$\frac{\mathrm{tan}\:\theta+\mathrm{tan}\:\mathrm{2}\theta}{\mathrm{1}−\mathrm{tan}\:\theta\:\mathrm{tan}\:\mathrm{2}\theta}=\sqrt{\mathrm{3}} \\ $$$$\mathrm{tan}\:\mathrm{3}\theta=\sqrt{\mathrm{3}}…
Question Number 29581 by math solver last updated on 10/Feb/18 $${Let}\:{x}\:=\:\mathrm{4}{sin}^{\mathrm{2}} \mathrm{10}^{{o}} +\mathrm{4}{sin}^{\mathrm{2}} \mathrm{50}^{{o}} {cos}\mathrm{20}^{{o}} +{cos}\mathrm{80}^{{o}} \\ $$$${and}\:{y}\:=\:{cos}^{\mathrm{2}} \:\frac{\pi}{\mathrm{5}}+{cos}^{\mathrm{2}} \frac{\mathrm{2}\pi}{\mathrm{15}}+{cos}^{\mathrm{2}} \frac{\mathrm{8}\pi}{\mathrm{15}}. \\ $$$${find}\:{x}+{y}\:? \\ $$…
Question Number 29491 by math solver last updated on 09/Feb/18 $${If}\:\mathrm{4}{sinx}.{cosy}+\mathrm{2}{sinx}+\mathrm{2}{cosy}+\mathrm{1}=\mathrm{0} \\ $$$${where}\:{x},{y}\:\in\:\left[\mathrm{0},\mathrm{2}{pie}\right].\:{Find}\:{largest}\: \\ $$$${possible}\:{value}\:{of}\:{the}\:{sum}\:\left({x}+{y}\right). \\ $$ Answered by ajfour last updated on 09/Feb/18 $$\left(\mathrm{1}+\mathrm{2sin}\:{x}\right)\left(\mathrm{1}+\mathrm{2cos}\:{y}\right)=\mathrm{0}…
Question Number 29478 by math solver last updated on 09/Feb/18 $${the}\:{number}\:{of}\:{ordered}\:{pairs}\:\left({x},{y}\right) \\ $$$${of}\:{real}\:{numbers}\:{satisfying}\: \\ $$$$\mathrm{4}{x}^{\mathrm{2}} −\mathrm{4}{x}+\mathrm{2}={sin}^{\mathrm{2}} {y} \\ $$$${and}\:{x}^{\mathrm{2}} +{y}^{\mathrm{2}} \leqslant\:\mathrm{3}\:{is}\:? \\ $$ Answered by…
Question Number 29413 by math solver last updated on 08/Feb/18 Commented by math solver last updated on 08/Feb/18 $${q}.\mathrm{3}\:? \\ $$ Answered by beh.i83417@gmail.com last…
Question Number 94923 by peter frank last updated on 21/May/20 Answered by peter frank last updated on 31/Oct/20 Terms of Service Privacy Policy Contact: info@tinkutara.com
Question Number 29354 by NECx last updated on 08/Feb/18 $$\mathrm{3sin}\:^{\mathrm{2}} \theta\:−\mathrm{sin}\:\theta\mathrm{cos}\:\theta\:−\mathrm{4cos}\:^{\mathrm{2}} \theta=\mathrm{0} \\ $$$${find}\:{the}\:{values}\:{of}\:\theta\:{if}\:\theta\:{lies} \\ $$$${between}\:\mathrm{0}\:{and}\:\mathrm{360} \\ $$ Answered by mrW2 last updated on 08/Feb/18…