prove that sin(A+B)sin(A-B)/cos^2 A-sin^2 B+sin^2 Asin^2 B=sec^2 A -sec^2 B
prove that
cosA+cos2A+cos3A+cos4A/sinA+sin2A+sin3A+sin4A=cot5A/2
F.4 M2 maths！！
2010-05-31 12:14 am
回答 (2)
2010-05-31 12:40 am
✔ 最佳答案
(sin(A+B)sin(A-B)/(cos^2 A-sin^2 B))+sin^2 Asin^2 B=sec^2 A -sec^2 B??(cosA+cos2A+cos3A+cos4A)/(sinA+sin2A+sin3A+sin4A)=cot5A/2??
2010-05-30 16:40:27 補充：
As follows:
圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/04-52.jpg
圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/05-45.jpg
2010-05-30 17:40:23 補充：
http://i707.photobucket.com/albums/ww74/stevieg90/04-52.jpg
http://i707.photobucket.com/albums/ww74/stevieg90/05-45.jpg
2010-05-31 12:50 am
sor 4 my poor expression.
u still were able2 ans. it
you are a vyvyvy pro. mathematician .
u still were able2 ans. it
you are a vyvyvy pro. mathematician .
收錄日期: 2021-04-22 00:48:14
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