Category: Trigonometry

Question Number 191305 by Mingma last updated on 22/Apr/23 Commented by mr W last updated on 22/Apr/23 $$thereisnouniquesolution.butthere$$$$isa{r}_{min}.$$ Answered by…

Question Number 191275 by Mingma last updated on 22/Apr/23 Answered by mr W last updated on 22/Apr/23 Commented by mr W last updated on 22/Apr/23…

Question Number 191167 by Mingma last updated on 19/Apr/23 Terms of Service Privacy Policy Contact: info@tinkutara.com

Question Number 191144 by mathlove last updated on 19/Apr/23 Answered by witcher3 last updated on 20/Apr/23 $$\tan \left(\mathrm{a}\right)\tan \left(\mathrm{b}\right)=\frac{\cos (\mathrm{a}-\mathrm{b})-\cos (\mathrm{a}+\mathrm{b})}{\cos (\mathrm{a}-\mathrm{b})+\cos (\mathrm{a}+\mathrm{b})}.$$$$\tan \left(42\right)\tan \left(78\right)=\frac{\cos \left(36\right)+\cos \left(120\right)}{\cos \left(36\right)-\cos \left(120\right)}=\frac{2\cos \left(36\right)-1}{2\cos \left(36\right)+1}$$$$\tan \left(6\right)\tan \left(66\right)=\frac{\cos \left(60\right)-\cos \left(72\right)}{\cos \left(60\right)+\cos \left(72\right)}$$$$=\frac{1-2\cos \left(72\right)}{1+2\cos \left(72\right)}$$$$\Leftrightarrow\frac{\mathrm{1}−\mathrm{2cos}\left(\mathrm{72}\right)}{\mathrm{1}+\mathrm{2cos}\left(\mathrm{72}\right)}.\frac{\mathrm{2cos}\left(\mathrm{36}\right)−\mathrm{1}}{\mathrm{2cos}\left(\mathrm{36}\right)+\mathrm{1}}=\mathrm{1}…

Question Number 190993 by mathlove last updated on 16/Apr/23 $${sin}^{2}x\cdot {cos}^{2}x=?$$ Answered by cortano12 last updated on 16/Apr/23 $$=\frac{1}{4}\sin {}^{2}2\mathrm{x}$$…