Menu Close

Category: Trigonometry

Montrer-que-x-R-cos-sinx-gt-sin-cosx-

Question Number 120029 by Ar Brandon last updated on 28/Oct/20 $$\mathrm{Montrer}\:\mathrm{que}\:\forall\mathrm{x}\in\mathbb{R} \\ $$$$\mathrm{cos}\left(\mathrm{sinx}\right)>\mathrm{sin}\left(\mathrm{cosx}\right) \\ $$ Commented by soumyasaha last updated on 29/Oct/20 $$\:\:\:\:\pi/\mathrm{2}\:\approx\:\mathrm{1}.\mathrm{57}\:\:\:\mathrm{and}\:\sqrt{\mathrm{2}}\:\approx\:\mathrm{1}.\mathrm{41} \\ $$$$\:\:\therefore\:\sqrt{\mathrm{2}}\:<\:\pi/\mathrm{2}…

show-that-tan-tan-2-5-tan-4-5-tan-6-5-tan-8-5-5tan-5-

Question Number 54480 by 951172235v last updated on 04/Feb/19 $$\mathrm{show}\:\mathrm{that} \\ $$$$\mathrm{tan}\:\alpha\:+\mathrm{tan}\:\left(\alpha+\frac{\mathrm{2}\overset{−} {\Lambda}}{\mathrm{5}}\right)\:+\mathrm{tan}\:\left(\alpha+\frac{\mathrm{4}\overset{−} {\Lambda}}{\mathrm{5}}\right)\:+\mathrm{tan}\:\left(\alpha+\frac{\mathrm{6}\overset{−} {\Lambda}}{\mathrm{5}}\right)\:+\:\mathrm{tan}\:\left(\alpha+\frac{\mathrm{8}\overset{−} {\Lambda}}{\mathrm{5}}\right)\:=\:\mathrm{5tan}\:\mathrm{5}\alpha \\ $$ Answered by tanmay.chaudhury50@gmail.com last updated on 05/Feb/19…

If-A-B-C-are-angle-of-a-triangle-show-that-tanA-tanB-tanC-tanA-tanB-tanC-

Question Number 54472 by Tawa1 last updated on 04/Feb/19 $$\mathrm{If}\:\mathrm{A},\:\mathrm{B},\:\mathrm{C}\:\:\mathrm{are}\:\mathrm{angle}\:\mathrm{of}\:\mathrm{a}\:\mathrm{triangle},\:\:\mathrm{show}\:\mathrm{that} \\ $$$$\:\:\:\mathrm{tanA}\:+\:\mathrm{tanB}\:+\:\mathrm{tanC}\:\:=\:\:\mathrm{tanA}\:\mathrm{tanB}\:\mathrm{tanC} \\ $$ Answered by math1967 last updated on 04/Feb/19 $${A}+{B}+{C}=\pi \\ $$$$\Rightarrow{A}+{B}=\pi−{C} \\…

Question-185511

Question Number 185511 by mathlove last updated on 23/Jan/23 Answered by Frix last updated on 23/Jan/23 $$\frac{\mathrm{1}}{\mathrm{2}−\sqrt{\mathrm{3}}}=\mathrm{2}+\sqrt{\mathrm{3}}={t} \\ $$$${t}^{−\mathrm{cos}\:{x}} ={t}^{\mathrm{sin}\:{x}} \\ $$$$−\mathrm{cos}\:{x}\:=\mathrm{sin}\:{x} \\ $$$$\frac{\mathrm{cos}\:{x}}{\mathrm{sin}\:{x}}=−\mathrm{1} \\…

Question-185486

Question Number 185486 by sonukgindia last updated on 22/Jan/23 Answered by a.lgnaoui last updated on 23/Jan/23 $$\mathrm{A}−\left(\mathrm{B}+\mathrm{C}\right)=\mathrm{0} \\ $$$$\mathrm{A}+\mathrm{B}+\mathrm{C}=\mathrm{2}\left(\mathrm{B}+\mathrm{C}\right)=\mathrm{2A} \\ $$$$\mathrm{A}+\mathrm{B}−\mathrm{C}=\mathrm{A}−\left(\mathrm{B}+\mathrm{C}\right)+\mathrm{2B}=\mathrm{2B} \\ $$$$\mathrm{A}−\mathrm{B}+\mathrm{C}=\mathrm{A}−\left(\mathrm{B}+\mathrm{C}\right)+\mathrm{2C}=\mathrm{2C} \\ $$$$…

sin-70-cos-50-sin-260-cos-280-

Question Number 119919 by bramlexs22 last updated on 28/Oct/20 $$\:\mathrm{sin}\:\mathrm{70}°\:\mathrm{cos}\:\mathrm{50}°\:+\:\mathrm{sin}\:\mathrm{260}°\:\mathrm{cos}\:\mathrm{280}°\:=? \\ $$ Answered by bobhans last updated on 28/Oct/20 $$\Leftrightarrow\mathrm{sin}\:\mathrm{70}°\:\mathrm{cos}\:\mathrm{50}°+\left(−\mathrm{cos}\:\mathrm{10}°\right)\left(\mathrm{sin}\:\mathrm{10}°\right)= \\ $$$$\:\:\frac{\mathrm{1}}{\mathrm{2}}\left(\mathrm{sin}\:\mathrm{120}°+\mathrm{sin}\:\mathrm{20}°\right)−\frac{\mathrm{1}}{\mathrm{2}}\mathrm{sin}\:\mathrm{20}°= \\ $$$$\:\:\frac{\mathrm{1}}{\mathrm{2}}×\frac{\mathrm{1}}{\mathrm{2}}\sqrt{\mathrm{3}}\:=\:\frac{\sqrt{\mathrm{3}}}{\mathrm{4}} \\…

Question-185426

Question Number 185426 by sonukgindia last updated on 21/Jan/23 Answered by Frix last updated on 21/Jan/23 $${u}=\mathrm{tan}\:{a}\:\wedge{v}=\mathrm{tan}\:{b}\:\Rightarrow \\ $$$$\frac{{u}+{v}}{\mathrm{1}−{uv}}=\frac{\mathrm{4}{v}}{\mathrm{3}−{v}^{\mathrm{2}} }\:\Rightarrow\:{u}=\frac{{v}}{\mathrm{3}}\:\Rightarrow\:\mathrm{answer}\:\mathrm{is}\:\mathrm{3} \\ $$ Terms of Service…

Question-185320

Question Number 185320 by mathlove last updated on 20/Jan/23 Answered by SEKRET last updated on 20/Jan/23 $$\:\boldsymbol{\mathrm{sin}}\left(\mathrm{2}\boldsymbol{\mathrm{a}}\right)=\mathrm{2}\boldsymbol{\mathrm{sin}}\left(\boldsymbol{\mathrm{a}}\right)\:\boldsymbol{\mathrm{cos}}\left(\boldsymbol{\mathrm{a}}\right) \\ $$ Answered by SEKRET last updated on…