Category: Trigonometry

Question Number 77178 by jagoll last updated on 04/Jan/20 $$$$$$given{\cos }^{-1}\left(x\right)+{\cos }^{-1}\left(y\right)+{\cos }^{-1}\left(z\right)=\pi$$$$andx+y+z=\frac{3}{2}$$$$provethatx=y=z.$$ Answered by john santu…

Question Number 77123 by mathocean1 last updated on 03/Jan/20 $$\mathrm{ABC}\mathrm{is}\mathrm{a}\mathrm{non}-\mathrm{right}\mathrm{triangle}.$$$$1)\mathrm{Demonstrate}\mathrm{that}$$$$\tan (\hat{\mathrm{A}}+\hat{\mathrm{B}})=-\tan \hat{\mathrm{C}}.$$$$\left.\mathrm{1}\right)\:\mathrm{By}\:\mathrm{using}\:\mathrm{tan}\left(\hat {\mathrm{A}}+\hat {\mathrm{B}}\right)=\frac{\mathrm{tan}\hat {\mathrm{A}}+\mathrm{tan}\hat {\mathrm{B}}}{\mathrm{1}−\mathrm{tan}\hat {\mathrm{A}tan}\hat {\mathrm{B}}}…

Question Number 77041 by mathocean1 last updated on 02/Jan/20 $$\mathrm{solve}\mathrm{in}[0;\pi ]$$$$\sin x-{\sin }^{3}x=1-\cos 2x$$ Answered by mind is power last updated on 02/Jan/20 $$\Leftrightarrow…

Question Number 11475 by tawa last updated on 26/Mar/17 Answered by sm3l2996 last updated on 26/Mar/17 $$\mathrm{Question}105:\left(\mathrm{B}\right)$$$$\mathrm{Question}106:$$$$\mathrm{\Delta }\mathrm{AFD}=\frac{{\mathrm{x}}^2}{2}=\frac{25}{2}=12.5\left(\mathrm{C}\right)$$ Commented…

Question Number 11456 by Joel576 last updated on 26/Mar/17 $$\sin x-\cos x=a,\frac{\pi }{4}⩽x⩽\frac{\pi }{2}$$$$\mathrm{Which}\mathrm{statement}\mathrm{is}\mathrm{correct}?$$$$\left(1\right){\sin }^{2}x-{\cos }^{2}x=-\frac{1}{2}\sqrt{3+2a^2-a^4}$$$$\left(\mathrm{2}\right)\:\mathrm{sin}^{\mathrm{4}} \:{x}\:+\:\mathrm{cos}^{\mathrm{4}} \:{x}\:=\:\frac{\mathrm{1}}{\mathrm{8}}\left(−\mathrm{3}{a}^{\mathrm{4}} \:+\:\mathrm{6}{a}^{\mathrm{2}} \:+\:\mathrm{5}\right) \…