Question Number 208742 by efronzo1 last updated on 22/Jun/24 Terms of Service Privacy Policy Contact: info@tinkutara.com
Question Number 208638 by lmcp1203 last updated on 20/Jun/24 Terms of Service Privacy Policy Contact: info@tinkutara.com
Question Number 208437 by efronzo1 last updated on 16/Jun/24 Answered by som(math1967) last updated on 16/Jun/24 $$\:{a}={sin}\mathrm{84}+{cos}\mathrm{66} \\ $$$$\Rightarrow{a}={sin}\mathrm{84}+{sin}\mathrm{24} \\ $$$$\Rightarrow{a}=\mathrm{2}{sin}\mathrm{54}{cos}\mathrm{30} \\ $$$$\:\therefore{a}=\mathrm{2}×\frac{\sqrt{\mathrm{5}}+\mathrm{1}}{\mathrm{4}}×\frac{\sqrt{\mathrm{3}}}{\mathrm{2}}=\frac{\sqrt{\mathrm{3}}\left(\sqrt{\mathrm{5}}+\mathrm{1}\right)}{\mathrm{4}} \\ $$$${b}={sin}\mathrm{48}−{sin}\mathrm{12}…
Question Number 208252 by efronzo1 last updated on 09/Jun/24 $$\:\mathrm{cos}\:\left(\frac{\mathrm{2}\pi}{\mathrm{21}}\right)\mathrm{cos}\:\left(\frac{\mathrm{4}\pi}{\mathrm{21}}\right)\mathrm{cos}\:\left(\frac{\mathrm{8}\pi}{\mathrm{21}}\right)\mathrm{cos}\:\left(\frac{\mathrm{10}\pi}{\mathrm{22}}\right)\mathrm{cos}\:\left(\frac{\mathrm{16}\pi}{\mathrm{21}}\right)\mathrm{cos}\:\left(\frac{\mathrm{20}\pi}{\mathrm{21}}\right)=? \\ $$ Answered by som(math1967) last updated on 09/Jun/24 $$\:{let}\:\frac{\pi}{\mathrm{21}}={x} \\ $$$${cos}\mathrm{2}{xcos}\mathrm{4}{xcos}\mathrm{8}{xcos}\mathrm{10}{xcos}\mathrm{16}{xcos}\mathrm{20}{x} \\ $$$${cosxcos}\mathrm{2}{xcos}\mathrm{4}{xcos}\mathrm{8}{xcos}\mathrm{10}{xcos}\mathrm{5}{x} \\…
Question Number 208130 by efronzo1 last updated on 06/Jun/24 $$\:\:\frac{\mathrm{1}}{\mathrm{cos}\:\mathrm{x}−\mathrm{cos}\:\mathrm{3x}}\:+\:\frac{\mathrm{1}}{\mathrm{cos}\:\mathrm{x}−\mathrm{cos}\:\mathrm{5x}}\:+ \\ $$$$\:\frac{\mathrm{1}}{\mathrm{cos}\:\mathrm{x}−\mathrm{cos}\:\mathrm{7x}}\:+\:\frac{\mathrm{1}}{\mathrm{cos}\:\mathrm{x}−\mathrm{cos}\:\mathrm{11x}}=?\: \\ $$ Answered by Ghisom last updated on 06/Jun/24 $$\mathrm{let}\:{c}_{{n}} =\mathrm{cos}\:{nx} \\ $$$$=−\frac{\mathrm{2}{c}_{\mathrm{10}}…
Question Number 208104 by Coolkhid999 last updated on 05/Jun/24 Terms of Service Privacy Policy Contact: info@tinkutara.com
Question Number 207925 by lmcp1203 last updated on 30/May/24 Commented by lmcp1203 last updated on 31/May/24 $${proof}\:\alpha\:=\mathrm{20} \\ $$ Answered by Frix last updated on…
Question Number 207516 by MATHEMATICSAM last updated on 17/May/24 $$\mathrm{3}\left(\mathrm{sin}\theta\:−\:\mathrm{cos}\theta\right)^{\mathrm{4}} \:+\:\mathrm{6}\left(\mathrm{sin}\theta\:+\:\mathrm{cos}\theta\right)^{\mathrm{2}} \\ $$$$+\:\mathrm{4}\left(\mathrm{sin}^{\mathrm{6}} \theta\:+\:\mathrm{cos}^{\mathrm{6}} \theta\right)\:=\:? \\ $$ Commented by A5T last updated on 17/May/24 $${Did}\:{you}\:{edit}\:{this}\:{question}\:{to}\:{change}\:{something}?…
Question Number 207434 by Frix last updated on 22/May/24 $$\mathrm{Relating}\:\mathrm{to}\:\mathrm{question}\:\mathrm{207407} \\ $$$${x}^{\mathrm{3}} −\mathrm{12}{x}^{\mathrm{2}} +\mathrm{27}{x}−\mathrm{17}=\mathrm{0} \\ $$$$\mathrm{Let}\:{x}={t}+\mathrm{4} \\ $$$${t}^{\mathrm{3}} −\mathrm{21}{t}−\mathrm{37}=\mathrm{0} \\ $$$$\mathrm{The}\:\mathrm{Trigonometric}\:\mathrm{Solution}\:\mathrm{gives}\:\mathrm{these}: \\ $$$${x}_{\mathrm{1}} =\mathrm{4}−\mathrm{2}\sqrt{\mathrm{7}}\mathrm{cos}\:\frac{\pi+\mathrm{2sin}^{−\mathrm{1}} \:\frac{\mathrm{37}\sqrt{\mathrm{7}}}{\mathrm{98}}}{\mathrm{6}}…
Question Number 207065 by manxsol last updated on 05/May/24 $$ \\ $$$$\:\:\:{f}\left({x}\right)=\left[{cos}\mathrm{2}{x}+{cos}\mathrm{3}{x}\right]\left[{cos}\mathrm{4}{x}+{cos}\mathrm{6}{x}\right]\left[\left[{cosx}+{cos}\mathrm{5}{x}\right]\right. \\ $$$${evaluar}\:\:\:{f}\left(\frac{\mathrm{2}\pi}{\mathrm{13}}\right)\:\: \\ $$ Answered by Berbere last updated on 06/May/24 $$\left.\mathrm{4}{cos}\left({x}\right){cos}\left(\mathrm{5}{x}\right){cos}\left(\mathrm{2}{x}\right){cos}\left(\mathrm{3}{x}\right).\left[{cos}\left(\mathrm{2}{x}\right)+{cos}\left(\:\mathrm{3}{x}\right)\right]\right]{a}\mathrm{2}\left(\right. \\…