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Category: Trigonometry

Question-172189

Question Number 172189 by Mikenice last updated on 23/Jun/22 Answered by Mathspace last updated on 24/Jun/22 $${let}\:{u}_{{n}} =\prod_{{k}=\mathrm{1}} ^{{n}} \left(\varphi\left({a}+\frac{{kb}}{{n}}\right)\right)^{\frac{\mathrm{1}}{{n}}} \\ $$$$\Rightarrow{lim}_{{n}\rightarrow+\infty} {ln}\left({u}_{{n}} \right) \\…

Given-cos-x-cos-y-3-2-cos-x-y-where-x-y-0-2pi-find-x-amp-y-

Question Number 106579 by john santu last updated on 06/Aug/20 $$\mathcal{G}\mathrm{iven}\:\mathrm{cos}\:\mathrm{x}+\mathrm{cos}\:\mathrm{y}=\frac{\mathrm{3}}{\mathrm{2}}+\mathrm{cos}\:\left(\mathrm{x}+\mathrm{y}\right) \\ $$$$\mathrm{where}\:\mathrm{x},\mathrm{y}\:\in\:\left[\mathrm{0},\mathrm{2}\pi\:\right].\:\mathrm{find}\:\mathrm{x}\:\&\:\mathrm{y}\: \\ $$ Answered by bobhans last updated on 06/Aug/20 $$\mathrm{cos}\:\mathrm{x}+\mathrm{cos}\:\mathrm{y}\:=\:\frac{\mathrm{3}}{\mathrm{2}}+\mathrm{cos}\:\mathrm{xcos}\:\mathrm{y}−\mathrm{sin}\:\mathrm{xsin}\:\mathrm{y} \\ $$$$\mathrm{cos}\:\mathrm{x}+\mathrm{cos}\:\mathrm{y}−\mathrm{cos}\:\mathrm{xcos}\:\mathrm{y}+\mathrm{sin}\:\mathrm{xsin}\:\mathrm{y}=\frac{\mathrm{3}}{\mathrm{2}}…

4cos-x-cos-2x-cos-3x-1-

Question Number 106468 by bemath last updated on 05/Aug/20 $$\mathrm{4cos}\:\mathrm{x}\:\mathrm{cos}\:\mathrm{2x}\:\mathrm{cos}\:\mathrm{3x}\:=\:\mathrm{1} \\ $$ Answered by john santu last updated on 05/Aug/20 $$\mathrm{recall}\::\:\mathrm{2cos}\:\mathrm{3x}\:\mathrm{cos}\:\mathrm{x}\:=\:\mathrm{cos}\:\mathrm{4x}+\mathrm{cos}\:\mathrm{2x} \\ $$$$\Rightarrow\mathrm{2}\left\{\mathrm{cos}\:\mathrm{4x}+\mathrm{cos}\:\mathrm{2x}\right\}\mathrm{cos}\:\mathrm{2x}=\mathrm{1} \\ $$$$\mathrm{2}\left\{\mathrm{2cos}\:^{\mathrm{2}}…

2a-sin-25-a-51-0-find-a-

Question Number 40875 by Tawa1 last updated on 28/Jul/18 $$\mathrm{2a}\:\mathrm{sin}\left(\frac{\mathrm{25}}{\mathrm{a}}\right)\:−\:\mathrm{51}\:=\:\mathrm{0},\:\:\mathrm{find}\:\mathrm{a} \\ $$ Answered by MrW3 last updated on 29/Jul/18 $${let}'{s}\:{have}\:{a}\:{look}\:{at}\:{the}\:{function}\:{f}\left({x}\right)=\frac{\mathrm{sin}\:\left({x}\right)}{{x}}. \\ $$$${we}\:{know}\:{following}\:{about}\:{it}: \\ $$$${f}\left(−{x}\right)={f}\left({x}\right)\:\Rightarrow{symmetric} \\…