Category: Trigonometry

Question Number 74130 by mathocean1 last updated on 19/Nov/19 $$\mathrm{h}\mathrm{e}\mathrm{l}\mathrm{l}\mathrm{o}]\mathrm{help}\mathrm{me}\mathrm{to}\mathrm{solve}\mathrm{it}\mathrm{in}]-\mathrm{\Pi };\mathrm{\Pi }]\times ]-\mathrm{\Pi };\mathrm{\Pi }]\mathrm{please}$$$$\{\begin{array}{l}\mathrm{x}-\mathrm{y}=\frac{\mathrm{\Pi }}{6}\\ \mathrm{cosx}-\sqrt{3}\mathrm{cosy}=-\frac{1}{2}\end{array}$$ Answered by Tanmay chaudhury last updated on 19/Nov/19 $$cos(\frac{\pi }{6}+y)-\sqrt{3}cosy=\frac{-1}{2}$$$$\frac{\sqrt{\mathrm{3}}}{\mathrm{2}}{cosy}−\frac{\mathrm{1}}{\mathrm{2}}{siny}−\sqrt{\mathrm{3}}\:{cosy}=\frac{−\mathrm{1}}{\mathrm{2}}…

Question Number 8503 by MNG last updated on 13/Oct/16 $$Q.1sinA+sinB+sinC=4cos\frac{A}{2}cos$$$$\frac{B}{2}cos\frac{C}{2}.$$$$Q.2cosAcosB-cosC=4cos\frac{A}{2}cos\frac{B}{2}$$$$cos\frac{C}{2}-1$$$$$$$$Q.3\frac{sin2A+sin2B+sin2C}{sinA+sinB+sinC}=8sin\frac{A}{2}$$$$sin\frac{B}{2}sin\frac{C}{2}$$$$ \…

Question Number 139521 by mnjuly1970 last updated on 28/Apr/21 $$\text{You can't use 'macro parameter character \#' in math mode}$$$$if{\left(pq\right)}^{{sin}^2\left(x\right)}+{\left(pq\right)}^{{cos}^2\left(x\right)}=p+q$$$$thentan\left(x\right)=?$$ Answered by qaz last updated…

Question Number 8403 by rhm last updated on 10/Oct/16 $$(Q.1)cos4A=1-8{cos}^{2}A+8{cos}^{2}A$$$$(Q.2)\frac{sec8A-1}{sec4A-1}=\frac{tan8A}{tan2A}$$$$(Q.3)tanA+tan({60}^0+A)+tan({120}^0$$$$+4)=3tan3A$$$$\left({Q}.\mathrm{4}\right)\:\:\:{sinA}\:{sin}\:\left(\mathrm{60}^{\mathrm{0}} −{A}\right)\:\:{sin}\left(\mathrm{60}^{\mathrm{0}} +{A}\right)\: \…

Question Number 139409 by henderson last updated on 26/Apr/21 $$\mathrm{hi}!$$$$\mathrm{prove}\mathrm{this}:$$$$cos\frac{\pi }{10}+cos\frac{4\pi }{10}+cos\frac{6\pi }{10}+cos\frac{9\pi }{10}=0.$$$$(\mathrm{by}\mathrm{the}\mathrm{easiest}\mathrm{possible}\mathrm{way}\dots !)$$ Answered by mr W last updated on…