Question Number 64498 by slotto last updated on 18/Jul/19 $$\mathrm{please},\:\mathrm{anyone}\:\mathrm{help}\:\mathrm{me}\:\mathrm{to}\:\mathrm{solve}\:\mathrm{this} \\ $$$$\mathrm{i}.\:\underset{\mathrm{k}=\mathrm{1}} {\overset{\mathrm{n}} {\sum}}\mathrm{cos}\left(\frac{\mathrm{k}^{\mathrm{2}} \pi}{\mathrm{n}}\right) \\ $$$$\mathrm{ii}.\:\underset{\mathrm{k}=\mathrm{1}} {\overset{\mathrm{n}} {\Sigma}}\mathrm{sin}\left(\frac{\mathrm{k}^{\mathrm{2}} \pi}{\mathrm{n}}\right) \\ $$$$\mathrm{thank}\:\mathrm{you}. \\ $$ Terms…
Question Number 129958 by bemath last updated on 21/Jan/21 $$\:\mathrm{3}+\mathrm{cos}\:\left(\mathrm{6x}\right)\:=\:\mathrm{2}\:\left(\frac{\mathrm{sin}\:\mathrm{3x}}{\mathrm{cos}\:\mathrm{4x}}\right)−\mathrm{4tan}\:^{\mathrm{2}} \left(\mathrm{4x}\right) \\ $$ Answered by MJS_new last updated on 21/Jan/21 $${s}=\mathrm{sin}\:{x} \\ $$$$… \\ $$$${s}^{\mathrm{14}}…
Question Number 64299 by mathmax by abdo last updated on 16/Jul/19 Terms of Service Privacy Policy Contact: info@tinkutara.com
Question Number 129807 by bramlexs22 last updated on 19/Jan/21 $$\:\mathrm{8}.\left(\mathrm{1}+\mathrm{sin}\:\frac{\pi}{\mathrm{8}}\right)\left(\mathrm{1}+\mathrm{sin}\frac{\mathrm{3}\pi}{\mathrm{8}}\right)\left(\mathrm{1}−\mathrm{sin}\:\frac{\mathrm{5}\pi}{\mathrm{8}}\right)\left(\mathrm{1}−\mathrm{sin}\:\frac{\mathrm{7}\pi}{\mathrm{8}}\right)=?\: \\ $$ Answered by EDWIN88 last updated on 19/Jan/21 $$\:\mathrm{sin}\:\mathrm{x}\:=\:\mathrm{sin}\:\left(\pi−\mathrm{x}\right) \\ $$$$\:\mathrm{sin}\:\frac{\mathrm{3}\pi}{\mathrm{8}}=\mathrm{sin}\:\frac{\mathrm{5}\pi}{\mathrm{8}}\:\mathrm{and}\:\mathrm{sin}\:\frac{\mathrm{7}\pi}{\mathrm{8}}=\mathrm{sin}\:\frac{\pi}{\mathrm{8}} \\ $$$$\Leftrightarrow\:\mathrm{8}\left(\mathrm{1}+\mathrm{sin}\:\frac{\pi}{\mathrm{8}}\right)\left(\mathrm{1}−\mathrm{sin}\:\frac{\pi}{\:\mathrm{8}}\right)\left(\mathrm{1}+\mathrm{sin}\:\frac{\mathrm{3}\pi}{\mathrm{8}}\right)\left(\mathrm{1}−\mathrm{sin}\:\frac{\mathrm{3}\pi}{\mathrm{8}}\right)= \\…
Question Number 129801 by bramlexs22 last updated on 19/Jan/21 $$\:\mathrm{cot}\:\mathrm{15}°\:\mathrm{cot}\:\mathrm{16}°\:\mathrm{cot}\:\mathrm{17}°…\:\mathrm{cot}\:\mathrm{75}°= \\ $$ Answered by EDWIN88 last updated on 19/Jan/21 $$=\mathrm{1} \\ $$$$\:\left[\:\mathrm{cot}\:\mathrm{15}°=\mathrm{tan}\:\mathrm{75}°\:\mathrm{etc}\:\right]\: \\ $$ Terms…
Question Number 129719 by bramlexs22 last updated on 18/Jan/21 $$\:\:\mathrm{cos}\:\left(\pi\mathrm{sin}\:\left(\frac{\mathrm{x}}{\mathrm{3}}\right)\right)=\mathrm{sin}\:\left(\pi\mathrm{cos}\:\left(\frac{\mathrm{x}}{\mathrm{3}}\right)\right) \\ $$$$\:\:\mathrm{x}\:=? \\ $$$$ \\ $$ Answered by liberty last updated on 18/Jan/21 $$\:\mathrm{cos}\:\left(\pi\mathrm{sin}\:\frac{\mathrm{x}}{\mathrm{3}}\right)=\mathrm{cos}\:\left(\frac{\pi}{\mathrm{2}}−\pi\mathrm{cos}\:\frac{\mathrm{x}}{\mathrm{3}}\right) \\…
Question Number 129712 by liberty last updated on 18/Jan/21 Commented by bemath last updated on 18/Jan/21 $$\mathrm{edit}\:\mathrm{the}\:\mathrm{last}\:\mathrm{line}\equiv\:\frac{\mathrm{3}−\mathrm{0}+\frac{\mathrm{3}}{\mathrm{4}}−\frac{\mathrm{3}}{\mathrm{8}}}{\mathrm{1}−\mathrm{0}−\frac{\mathrm{3}}{\mathrm{4}}+\frac{\mathrm{1}}{\mathrm{8}}}=\mathrm{9} \\ $$ Commented by liberty last updated on…
Question Number 64173 by Eminem last updated on 14/Jul/19 $${show}\:{tbat}\:\underset{{k}=\mathrm{1}} {\overset{{n}} {\prod}}\left(\mathrm{1}−\frac{{sin}^{\mathrm{2}} \left(\frac{\theta}{\mathrm{2}{n}}\right)}{{sin}^{\mathrm{2}} \left(\frac{\mathrm{2}{k}−\mathrm{1}}{\mathrm{4}}\pi\right)}\right)={cos}\left(\theta\right) \\ $$ Commented by Prithwish sen last updated on 15/Jul/19 $$\mathrm{Is}'\mathrm{nt}\:\mathrm{it}\:\mathrm{cos}^{\mathrm{n}}…
Question Number 129360 by bramlexs22 last updated on 15/Jan/21 $$\begin{cases}{\mathrm{sin}\:{a}\:+\:\mathrm{sin}\:{b}\:=\:\frac{\mathrm{1}}{\mathrm{3}}}\\{\mathrm{cos}\:{a}+\mathrm{cos}\:{b}\:=\:\frac{\mathrm{5}}{\mathrm{3}}}\end{cases} \\ $$$$\:\:\:\:\mathrm{cos}^{\mathrm{2}} \:\left({a}+{b}\right)\:=?\: \\ $$ Commented by bramlexs22 last updated on 15/Jan/21 $$\:\mathrm{nice}\:\mathrm{trigonometry} \\ $$…
Question Number 63747 by Tony Lin last updated on 08/Jul/19 $${What}\:{does}\:{sin}^{−\mathrm{2}} {x}\:{mean}? \\ $$ Commented by MJS last updated on 08/Jul/19 $$\mathrm{that}'\mathrm{s}\:\mathrm{the}\:\mathrm{question}… \\ $$$$\mathrm{we}'\mathrm{re}\:\mathrm{not}\:\mathrm{consequent}\:\mathrm{in}\:\mathrm{these}\:\mathrm{things} \\…