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Category: Trigonometry

Question-47150

Question Number 47150 by somil last updated on 05/Nov/18 Commented by maxmathsup by imad last updated on 05/Nov/18 weseethatcosθmustbe0θ[π2,π2][2π]changement=x=sinθgive$$\mathrm{3}\sqrt{\mathrm{1}−{x}^{\mathrm{2}} }=\mathrm{2}{x}^{\mathrm{2}} \:\Rightarrow\mathrm{9}\left(\mathrm{1}−{x}^{\mathrm{2}} \right)=\mathrm{4}{x}^{\mathrm{4}} \:\Rightarrow\mathrm{4}{x}^{\mathrm{4}}…

cos-cot-sin-tan-csc-sec-

Question Number 178181 by mathlove last updated on 13/Oct/22 cosαcotαsinαtanαcscαsecα=? Commented by Adedayo2000 last updated on 13/Oct/22 Recallcotα=1tanα=cosαsinα,cscα=1sinα,secα=1cosα=>(cosα)(cosαsinα)(sinα)(sinαcosα)(1sinα)(1cosα)$$=>\frac{\frac{{cos}^{\mathrm{2}} \alpha}{{sin}\alpha}−\frac{{sin}^{\mathrm{2}}…

1-cos80-3-sin80-

Question Number 178182 by mathlove last updated on 13/Oct/22 1cos803sin80=? Commented by cortano1 last updated on 13/Oct/22 1sin10°3cos10°=cos10°3sin10sin10°cos10°=4(12cos10°32sin10°)sin20°$$\:=\:\frac{\mathrm{4}\left(\mathrm{sin}\:\mathrm{30}°\:\mathrm{cos}\:\mathrm{10}°−\mathrm{cos}\:\mathrm{30}°\:\mathrm{sin}\:\mathrm{10}°\right)}{\mathrm{sin}\:\mathrm{20}°} \

Question-178153

Question Number 178153 by mnjuly1970 last updated on 13/Oct/22 Answered by mr W last updated on 13/Oct/22 2=(1+1a)(1+1b)(1+1c)(1+1a)3a1231a42=(1+1a)(1+1b)(1+1c)(1+1c)3$$\Rightarrow{c}\leqslant\frac{\mathrm{1}}{\:\sqrt[{\mathrm{3}}]{\mathrm{2}}−\mathrm{1}}\:\Rightarrow{c}\leqslant\mathrm{3} \

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Question Number 178087 by a.lgnaoui last updated on 12/Oct/22 unavionvolantahauteurh=4kmdusolavitessesupersonic(v)sachantquelavitessedusonalahauteurhestde300m/setqueletempsmisparlesonemisparlaviondepuisunpoint(c)estcspteparuneprrsonneavecun$${retard}\:{de}\:\mathrm{3}{s} \