Category: Trigonometry

Question Number 164426 by cortano1 last updated on 17/Jan/22 $$In\mathrm{\Delta }ABCif\{\begin{array}{l}\cot A.\cot C=\frac{1}{2}\\ \cot B.\cot C=\frac{1}{18}\end{array}$$$$then\tan C=?$$ Commented by bobhans last updated on 17/Jan/22 $$\mathrm{let}\tan \mathrm{C}=\mathrm{x}>0$$$$\:\Rightarrow\:\frac{\mathrm{2}}{\mathrm{x}}+\frac{\mathrm{18}}{\mathrm{x}}+\mathrm{x}\:=\:\frac{\mathrm{2}}{\mathrm{x}}\:.\frac{\mathrm{18}}{\mathrm{x}}.\:\mathrm{x} \…

Question Number 33116 by abdo imad last updated on 10/Apr/18 $$solveat[0,\pi ]cos\alpha +cos\left(2\alpha \right)+cos\left(3\alpha \right)=0$$ Answered by MJS last updated on 10/Apr/18 $$\cos 2\alpha ={2\cos }^2\alpha -1$$$$\mathrm{cos}\:\mathrm{3}\alpha=\mathrm{4cos}^{\mathrm{3}} \alpha−\mathrm{3cos}\:\alpha…

Question Number 163936 by cortano1 last updated on 12/Jan/22 $${\cos }^{-1}\left(\frac{x^2-1}{x^2+1}\right)+\frac{1}{2}{\tan }^{-1}\left(\frac{2x}{1-x^2}\right)=\frac{2\pi }{3}$$ Answered by mahdipoor last updated on 12/Jan/22 $${get}\:{cos}\beta=\frac{{x}^{\mathrm{2}}…

Question Number 32841 by alimudinade@gmail.com last updated on 03/Apr/18 $$A+B+C={180}^0$$$$3sinA+4cosB=6$$$$3cosA+4sinB=\sqrt{13}$$$$sinC=\dots .$$ Answered by hknkrc46 last updated on 04/Apr/18…

Question Number 98191 by behi83417@gmail.com last updated on 12/Jun/20 $$\mathbf{for}\mathbf{what}\mathbf{value}\mathbf{of}:\{\mathbf{x}\mid 0<\mathbf{x}<2\mathit{\pi }\}:$$$$4{\mathbf{cosec}}^2\mathbf{x}-9=\mathbf{cotx}$$ Answered by MJS last updated on 12/Jun/20 $$\mathrm{4cosec}^{\mathrm{2}} \:{x}\:−\mathrm{9}=\mathrm{cot}\:{x} \…