Category: Trigonometry

Question Number 135110 by faysal last updated on 10/Mar/21 Commented by Ñï= last updated on 10/Mar/21 $$Itry2csc2\theta =\tan \theta +\cot \theta .{It}^{\prime }stoocomplicate.$$$$Maybetherehaveeasyway.$$ Terms of Service Privacy…

Question Number 69500 by TawaTawa last updated on 24/Sep/19 Answered by MJS last updated on 24/Sep/19 $$\mathrm{the}\mathrm{shape}\mathrm{of}\mathrm{the}\mathrm{graph}\mathrm{looks}\mathrm{like}\mathrm{a}\mathrm{modified}$$$$f\left(x\right)=x^4-x^2$$$${f}\left(\mathrm{0}\right)\approx−\mathrm{7}\:\Rightarrow\:{f}\left({x}\right)\approx{x}^{\mathrm{4}} −{x}^{\mathrm{2}} −\mathrm{7} \…

Question Number 134902 by faysal last updated on 08/Mar/21 Commented by bobhans last updated on 08/Mar/21 $$\mathrm{use}\mathrm{that}(1+\sec 2\mathrm{x})\cot 2\mathrm{x}=\frac{1+\cos 2\mathrm{x}}{\sin 2\mathrm{x}}=\cot \mathrm{x}$$ Answered by bobhans last updated on…

Question Number 134801 by faysal last updated on 07/Mar/21 Answered by EDWIN88 last updated on 07/Mar/21 $$13\theta =\pi \Rightarrow \cos 13\theta =-1$$$$\mathrm{let}:\mathrm{z}=\cos \theta \cos 2\theta \cos 3\theta \cos 4\theta \cos 5\theta \cos 6\theta$$$$2\mathrm{z}\sin \theta =\sin 2\theta \cos 2\theta \cos 3\theta \cos 4\theta \cos 5\theta \cos 6\theta$$$$4\mathrm{z}\sin \theta =\sin 4\theta \cos 3\theta \cos 4\theta \cos 5\theta \cos 6\theta$$$$\mathrm{8z}\:\mathrm{sin}\:\theta\:=\:\mathrm{sin}\:\mathrm{8}\theta\:\mathrm{cos}\:\mathrm{3}\theta\:\mathrm{cos}\:\mathrm{5}\theta\:\mathrm{cos}\:\mathrm{6}\theta…

Question Number 134705 by bramlexs22 last updated on 06/Mar/21 $$\mathrm{Find}\mathrm{the}\mathrm{solution}$$$$(2-\sqrt{3})\cos 2\mathrm{x}+\sin 2\mathrm{x}=1$$ Answered by john_santu last updated on 06/Mar/21 $$Wecansetting\to \{\begin{array}{l}X=\cos 2x\\ Y=\sin 2x\end{array}$$$${so}\:{the}\:{equation}\:{becomes}\:\begin{cases}{\left(\mathrm{2}−\sqrt{\mathrm{3}}\right){X}+{Y}\:=\:\mathrm{1}}\{{X}^{\mathrm{2}} +{Y}^{\:\mathrm{2}}…