1, sin(x+40°) sin(x-40°)=3/5
2 sin7X-sinX=sin3X
3 cos3x=cos2xcosx
4 sin9x+sin5x+2sin^2 x =1
(general solution)
A maths
2007-04-22 5:16 am
回答 (1)
2007-04-22 6:06 am
✔ 最佳答案
For Q1, if there's no typo mistake, there is no solution and so, an estimation of the original question being sin(x+40°) + sin(x-40°)=3/5 is made as follows:圖片參考：http://i117.photobucket.com/albums/o61/billy_hywung/April07/Crazytrigo58.jpg
圖片參考：http://i117.photobucket.com/albums/o61/billy_hywung/April07/Crazytrigo59.jpg
參考: My Maths knowledge
收錄日期: 2021-04-12 20:31:52
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070421000051KK05021