Category: Trigonometry

Question Number 132850 by bramlexs22 last updated on 17/Feb/21 Answered by talminator2856791 last updated on 17/Feb/21 $$6$$ Terms of Service Privacy Policy Contact:…

Question Number 67083 by lalitchand last updated on 22/Aug/19 $$\mathrm{CosA}+\mathrm{CosB}+\mathrm{CosC}=1+4\mathrm{Cos}\left(\frac{\mathrm{B}+\mathrm{C}}{2}\right).\mathrm{Cos}\left(\frac{\mathrm{C}+\mathrm{A}}{2}\right).\mathrm{Cos}\left(\frac{\mathrm{A}+\mathrm{B}}{2}\right)=1+4\mathrm{Cos}\left(\frac{\mathrm{\Pi }-\mathrm{A}}{4}\right).\mathrm{Cos}\left(\frac{\mathrm{\Pi }-\mathrm{B}}{4}\right).\mathrm{Cos}\left(\frac{\mathrm{\Pi }-\mathrm{C}}{4}\right)$$$$\mathrm{prove}\mathrm{that}\mathrm{if}\mathrm{A}+\mathrm{B}+\mathrm{C}=\mathrm{\Pi }$$ Answered by Tanmay chaudhury last updated on 23/Aug/19 $$LHS$$$$\mathrm{2}{cos}\left(\frac{{A}+{B}}{\mathrm{2}}\right){cos}\left(\frac{{A}−{B}}{\mathrm{2}}\right)+\mathrm{1}−\mathrm{2}{sin}^{\mathrm{2}}…

Question Number 1407 by 112358 last updated on 29/Jul/15 $$Solvethefollowinginequality$$$$\frac{sinx+1}{cosx}⩽1$$$$where0⩽x<2\pi ,cosx\ne 0$$ Commented by 123456 last updated on 29/Jul/15 $${f}\left({x}\right)=\frac{\mathrm{sin}\:{x}+\mathrm{1}}{\mathrm{cos}\:{x}} \…

Question Number 132474 by bemath last updated on 14/Feb/21 $$\mathrm{maximum}\mathrm{value}\mathrm{of}$$$$\mathrm{f}\left(\mathrm{x}\right)=\sqrt{4\sin \left(\mathrm{x}\right)+1}-\cos \left(\mathrm{x}\right)$$$$\mathrm{is}$$ Commented by EDWIN88 last updated on 14/Feb/21 Commented by…

Question Number 132347 by Study last updated on 13/Feb/21 $$sin(2x+\frac{\pi }{4})-sin(2x+\frac{\pi }{3})=0x=?$$ Answered by EDWIN88 last updated on 13/Feb/21 $$\sin \mathrm{X}-\sin \mathrm{Y}=2\cos \left(\frac{\mathrm{X}+\mathrm{Y}}{2}\right)\sin \left(\frac{\mathrm{X}-\mathrm{Y}}{2}\right)$$$$\mathrm{where}\{\begin{array}{l}\mathrm{X}=2\mathrm{x}+\frac{\pi }{4}\\ \mathrm{Y}=2\mathrm{x}+\frac{\pi }{3}\end{array}$$$$\mathrm{sin}\:\left(\mathrm{2x}+\frac{\pi}{\mathrm{4}}\right)−\mathrm{sin}\:\left(\mathrm{2x}+\frac{\pi}{\mathrm{3}}\right)=\mathrm{0} \…