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Category: Trigonometry

show-that-If-a-2-b-2-c-2-are-in-A-P-the-cotA-cotB-cotC-are-also-in-A-P-

Question Number 46569 by scientist last updated on 28/Oct/18 $${show}\:{that}\:\:{If}\:{a}^{\mathrm{2}} ,{b}^{\mathrm{2}} ,{c}^{\mathrm{2}\:} \:{are}\:{in}\:{A}.{P}\:\:{the}\:{cotA},{cotB},{cotC}\:{are} \\ $$$${also}\:{in}\:{A}.{P} \\ $$ Answered by tanmay.chaudhury50@gmail.com last updated on 28/Oct/18 $$\frac{{sinA}}{{a}}=\frac{{sinB}}{{b}}=\frac{{sinc}}{{c}}={k}\left({say}\right)…

If-in-triangle-ABC-cosB-b-cosC-c-show-that-the-triangle-is-isosceles-

Question Number 46570 by scientist last updated on 28/Oct/18 $${If}\:{in}\:{triangle}\:{ABC}\:\:\:\frac{{cosB}}{{b}}\:=\frac{{cosC}}{{c}},\:{show}\:{that}\:{the} \\ $$$${triangle}\:{is}\:{isosceles} \\ $$ Answered by tanmay.chaudhury50@gmail.com last updated on 28/Oct/18 $$\frac{{sinA}}{{a}}=\frac{{sinB}}{{b}}=\frac{{sinC}}{{c}} \\ $$$$\frac{{cosB}}{{cosC}}=\frac{{sinB}}{{sinC}}=\frac{{b}}{{c}} \\…

Are-there-infinitely-many-solutions-to-sin-2-cos-90-2-

Question Number 112075 by Aina Samuel Temidayo last updated on 06/Sep/20 $$\mathrm{Are}\:\mathrm{there}\:\mathrm{infinitely}\:\mathrm{many}\:\mathrm{solutions}\:\mathrm{to} \\ $$$$\mathrm{sin}\left(\frac{\beta}{\mathrm{2}}\right)=\mathrm{cos}\left(\mathrm{90}−\frac{\beta}{\mathrm{2}}\right)\:? \\ $$ Commented by $@y@m last updated on 06/Sep/20 This is an identity. �� https://en.m.wikipedia.org/wiki/Identity_(mathematics) Commented…

Question-46472

Question Number 46472 by peter frank last updated on 27/Oct/18 Answered by tanmay.chaudhury50@gmail.com last updated on 27/Oct/18 $$\left({asin}\theta+{bcos}\theta\right)^{\mathrm{2}} ={c}^{\mathrm{2}} \\ $$$${a}^{\mathrm{2}} {sin}^{\mathrm{2}} \theta+{b}^{\mathrm{2}} {cos}^{\mathrm{2}} \theta+\mathrm{2}{absin}\theta{cos}\theta={c}^{\mathrm{2}}…

Question-177542

Question Number 177542 by peter frank last updated on 06/Oct/22 Answered by Frix last updated on 07/Oct/22 $$\mathrm{9}°={x} \\ $$$$\mathrm{27}°=\mathrm{3}{x} \\ $$$$\mathrm{tan}\:\left(\mathrm{90}°−{x}\right)\:=\frac{\mathrm{1}}{\mathrm{tan}\:{x}} \\ $$$$\mathrm{81}°=\mathrm{90}°−\mathrm{9}° \\…

The-angle-of-elevetion-of-the-top-of-a-tower-from-a-point-A-in-the-north-is-and-the-angle-of-the-top-of-the-tower-from-the-point-B-in-the-east-of-the-point-A-is-prove-that-the-height-of-the-tow

Question Number 177507 by peter frank last updated on 06/Oct/22 $$\mathrm{The}\:\mathrm{angle}\:\mathrm{of}\:\mathrm{elevetion}\:\mathrm{of}\:\mathrm{the} \\ $$$$\mathrm{top}\:\mathrm{of}\:\mathrm{a}\:\mathrm{tower}\:\mathrm{from}\:\mathrm{a}\:\mathrm{point}\: \\ $$$$\mathrm{A}\:\mathrm{in}\:\mathrm{the}\:\mathrm{north}\:\mathrm{is}\:\alpha\:\mathrm{and}\:\mathrm{the}\: \\ $$$$\mathrm{angle}\:\mathrm{of}\:\mathrm{the}\:\mathrm{top}\:\mathrm{of}\:\mathrm{the}\:\mathrm{tower} \\ $$$$\mathrm{from}\:\mathrm{the}\:\mathrm{point}\:\mathrm{B}\:\mathrm{in}\:\mathrm{the}\:\mathrm{east}\:\mathrm{of}\:\mathrm{the}\:\mathrm{point} \\ $$$$\mathrm{A}\:\mathrm{is}\:\beta\:.\mathrm{prove}\:\mathrm{that}\:\mathrm{the}\:\mathrm{height} \\ $$$$\mathrm{of}\:\mathrm{the}\:\mathrm{tower}\:\mathrm{is}\: \\ $$$$\frac{\mathrm{ABsin}\:\alpha\mathrm{sin}\:\mathrm{B}}{\:\sqrt{\mathrm{sin}\:^{\mathrm{2}}…

show-that-cos-7-1-2-2-3-4-6-

Question Number 46402 by scientist last updated on 25/Oct/18 $${show}\:{that}\:\mathrm{cos}\:\mathrm{7}\frac{\mathrm{1}}{\mathrm{2}}\:=\sqrt{\mathrm{2}}+\sqrt{\mathrm{3}}+\sqrt{\mathrm{4}}+\sqrt{\mathrm{6}} \\ $$ Commented by Meritguide1234 last updated on 25/Oct/18 $${it}\:{should}\:{be}\:{cot}\mathrm{7}\frac{\mathrm{1}}{\mathrm{2}} \\ $$ Answered by ajfour…