Question Number 133443 by mnjuly1970 last updated on 22/Feb/21 $$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:……{nice}\:\:\:\:\:\:{calculus}……. \\ $$$$\:\:{if}\:\:{a},{b},{c}\:\geqslant\mathrm{0} \\ $$$$\:\:\:\:{and}\:::\:\:\:\:{acos}^{\mathrm{2}} \left({x}\right)+{bsin}^{\mathrm{2}} \left({x}\right)\leqslant{c} \\ $$$$\:\:\:\:{then}\:\:{prove}\:{that}:: \\ $$$$\:\:\:\:\:\:\:\sqrt{{a}}\:{cos}^{\mathrm{2}} \left({x}\right)+\sqrt{{b}}\:{sin}^{\mathrm{2}} \left({x}\right)\leqslant\sqrt{{c}} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:…………. \\…
Question Number 133351 by bramlexs22 last updated on 21/Feb/21 Answered by mr W last updated on 22/Feb/21 $${a}=\mathrm{1},\:{b}=\mathrm{2},\:{c}=\sqrt{\mathrm{5}} \\ $$$$\Rightarrow{A}=\mathrm{1} \\ $$ Terms of Service…
Question Number 133347 by rs4089 last updated on 21/Feb/21 $${for}\:{a}\:{triangle}\:{ABC}\:… \\ $$$${find}\:{minimum}\:{value}\:{of}\: \\ $$$${CosA}.{CosB}.{CosC} \\ $$ Commented by mr W last updated on 21/Feb/21 $${i}\:{think}\:{there}\:{is}\:{no}\:{minimum},…
Question Number 133142 by bemath last updated on 19/Feb/21 $$\mathrm{If}\:\mathrm{sin}\:\left(\frac{\mathrm{23}\pi}{\mathrm{24}}\right)\:=\:\sqrt{\frac{\mathrm{2}\sqrt{\mathrm{p}}−\sqrt{\mathrm{q}}−\mathrm{1}}{\mathrm{4}\sqrt{\mathrm{r}}}} \\ $$$$\mathrm{then}\:\mathrm{the}\:\mathrm{value}\:\mathrm{of}\:\left(\mathrm{p}^{\mathrm{2}} +\mathrm{q}^{\mathrm{2}} −\mathrm{r}^{\mathrm{2}} \right)\:\mathrm{is} \\ $$$$\mathrm{equal}\:\mathrm{to}\: \\ $$ Answered by Ñï= last updated on…
Question Number 67495 by TawaTawa last updated on 28/Aug/19 Commented by Prithwish sen last updated on 28/Aug/19 $$\mathrm{sin}\left(\frac{\mathrm{5}}{\mathrm{2}}\pi+\mathrm{x}\right)=\mathrm{Cos}\left(\mathrm{x}+\frac{\mathrm{1}}{\mathrm{2}}−\frac{\mathrm{1}}{\mathrm{9}}\right)\Rightarrow\mathrm{Cosx}=\mathrm{Cos}\left(\mathrm{x}+\frac{\mathrm{7}}{\mathrm{18}}\right) \\ $$$$\mathrm{x}=\mathrm{2n}\pi\pm\left(\mathrm{x}+\frac{\mathrm{7}}{\mathrm{18}}\right)\:\:\:\mathrm{n}\in\:\mathbb{Z} \\ $$ Commented by TawaTawa…
Question Number 1961 by alib last updated on 26/Oct/15 $${Solve}… \\ $$$$ \\ $$$$\mathrm{1}+\:{sin}\:\mathrm{2}{x}\:=\:{sin}\:{x}\:+\:{cos}\:{x} \\ $$ Answered by Rasheed Soomro last updated on 26/Oct/15 $$\mathrm{1}+\:{sin}\:\mathrm{2}{x}\:=\:{sin}\:{x}\:+\:{cos}\:{x}…
Question Number 67464 by lalitchand last updated on 27/Aug/19 $$\mathrm{prove}\:\:\:\mathrm{Cos}\left(\frac{\mathrm{2}\pi}{\mathrm{7}}\right)+\mathrm{Cos}\left(\frac{\mathrm{4}\pi}{\mathrm{7}}\right)+\mathrm{Cos}\left(\frac{\mathrm{8}\pi}{\mathrm{7}}\right)=−\frac{\mathrm{1}}{\mathrm{2}} \\ $$ Answered by mind is power last updated on 27/Aug/19 $${Z}^{\mathrm{7}} −\mathrm{1}=\mathrm{0} \\ $$$$\Rightarrow\left({z}−\mathrm{1}\right)\left(\mathrm{1}+{z}+{z}^{\mathrm{2}}…
Question Number 1890 by Rasheed Soomro last updated on 21/Oct/15 $${Solve}\:{for}\:{x} \\ $$$$\:\:\:\:\:\:{tan}\:{x}\:+{tan}\:\mathrm{2}{x}\:−{tan}\:\mathrm{3}{x}\:=\mathrm{0} \\ $$$${Some}\:{one}\:{had}\:{posted}\:{this}\:{question}\:{and}\:{I}\:{had}\:{answered}\:{it} \\ $$$${but}\:{then}\:{thread}\:{was}\:{deleted}! \\ $$$${I}\:{think}\:{that}\:{the}\:{question}\:{is}\:{not}\:{importanceless}\:,\:{so}\:{I}\:{hav} \\ $$$${reposted}\:{it}. \\ $$ Commented by…
Question Number 1870 by alib last updated on 18/Oct/15 $${Solve}\: \\ $$$$ \\ $$$$\mathrm{2}{sin}\:\mathrm{2}{x}−\:\mathrm{3}\left({sin}\:{x}\:+\:{cos}\:{x}\right)\:+\:\mathrm{2}\:=\mathrm{0} \\ $$ Answered by 112358 last updated on 19/Oct/15 $$\mathrm{2}{sin}\mathrm{2}{x}−\mathrm{3}\left({sinx}+{cosx}\right)+\mathrm{2}=\mathrm{0} \\…
Question Number 67396 by Cmr 237 last updated on 26/Aug/19 Commented by mathmax by abdo last updated on 26/Aug/19 $${let}\:{P}\left({z}\right)\:=\:{z}^{\mathrm{2}{n}} \:+\mathrm{1}\:{let}\:{determine}\:{the}\:{roots}\:{of}\:{P}\left({z}\right) \\ $$$${P}\left({z}\right)=\mathrm{0}\:\Leftrightarrow\:{z}^{\mathrm{2}{n}} \:=−\mathrm{1}\:\:\Leftrightarrow\:\:{z}^{\mathrm{2}{n}} ={e}^{{i}\left(\mathrm{2}{k}+\mathrm{1}\right)\pi}…