sin-9-sin-21-sin-39-2-golden-ratio-m-n- Tinku Tara June 4, 2023 Differentiation 0 Comments FacebookTweetPin Question Number 153553 by mnjuly1970 last updated on 08/Sep/21 sin(9)+sin(21)+sin(39)=?φ2φ:=goldenratiom.n Answered by bramlexs22 last updated on 08/Sep/21 sin(9°)+sin(21°)+sin(39°)=2sin15°cos6°+sin(45°−6°)=2sin(45°−30°)cos6°+22cos6°−22sin6°=2cos6°(64−24)+22cos6°−22sin6°=62cos6°−22sin6°=6+24cos(6°−330°)=2cos324°=2cos(270°+54°)=2sin54°=2cos36°=2(1−2sin218°)=2(1−2(5−14)2)=2(1−(6−258))=2(2+258)=2(5+14)=22(5+12)=12φ=φ2 Commented by Tawa11 last updated on 08/Sep/21 greatsir Terms of Service Privacy Policy Contact: info@tinkutara.com FacebookTweetPin Post navigation Previous Previous post: Question-22481Next Next post: Question-88021 Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Comment * Name * Save my name, email, and website in this browser for the next time I comment.