Category: Trigonometry

Question Number 114627 by john santu last updated on 20/Sep/20 $$\sin A+\sin 2A+\sin 3A+\dots +\sin nA=??$$ Answered by mathmax by abdo last updated on 20/Sep/20 $$\mathrm{let}\:\mathrm{S}_{\mathrm{n}} \left(\mathrm{x}\right)\:=\mathrm{sinx}\:+\mathrm{sin}\left(\mathrm{2x}\right)+…+\mathrm{sin}\left(\mathrm{nx}\right)=\sum_{\mathrm{k}=\mathrm{0}} ^{\mathrm{n}}…

Question Number 180025 by cortano1 last updated on 06/Nov/22 $$4-2\cos \left(2\pi {(13\mathrm{x}+9)}^2\right)=5\sin \left(\pi {(13\mathrm{x}+9)}^2\right)$$$$\mathrm{x}=?$$ Answered by Frix last updated on 06/Nov/22 $$\mathrm{4}−\mathrm{2cos}\:\mathrm{2}\alpha\:=\mathrm{5sin}\:\alpha \…

Question Number 114409 by bemath last updated on 19/Sep/20 $$findsolutionsetofequation$$$$\sin x=2,x\in \mathbb{C}.$$ Answered by bobhans last updated on 19/Sep/20 $$\mathrm{sin}\:{x}\:=\:\frac{{e}^{{ix}} −{e}^{−{ix}} }{\mathrm{2}{i}}\:=\:\mathrm{2}\: \…

Question Number 48852 by vajpaithegrate@gmail.com last updated on 29/Nov/18 $$\mathrm{A}\mathrm{polygon}\mathrm{of}\mathrm{nine}\mathrm{sides}\mathrm{each}\mathrm{of}\mathrm{length}2$$$$\mathrm{is}\mathrm{inscribed}\mathrm{in}\mathrm{a}\mathrm{circle},\mathrm{the}\mathrm{radius}\mathrm{of}\mathrm{the}$$$$\mathrm{circle}$$$$\mathrm{ans}:\mathrm{cosec}20$$ Answered by tanmay.chaudhury50@gmail.com last updated on 29/Nov/18…

Question Number 48849 by vajpaithegrate@gmail.com last updated on 29/Nov/18 $$\mathrm{in}\left(0\pi \right)\mathrm{the}\mathrm{number}\mathrm{of}\mathrm{solutions}\mathrm{of}\mathrm{the}$$$$\mathrm{equation}\tan \theta +\tan 2\theta +\tan 3\theta =\tan \theta \tan 2\theta \tan 3\theta$$$$\mathrm{is}$$$$\mathrm{ans}:2$$ Answered by tanmay.chaudhury50@gmail.com last updated on 29/Nov/18…