將 cos26°寫成sinθ的形式
tan64°
我知answer,so要步驟
answer=sin26°
中二數題(要步驟 )
2009-06-18 5:04 am
回答 (2)
2009-06-18 5:50 am
✔ 最佳答案
cos26/tan64=cos26/(sin64/cos64)
=cos26cos64/sin64
=sin(90-26)sin(90-64)/sin64
=sin64sin26/sin64
=sin26
Note: cosx=sin(90-x) , for x being acute.
2009-06-17 21:52:42 補充：
should be for any real x ...
2009-06-18 6:03 am
cos26° / tan64°
= cos26° / (sin64° / cos64°) --->tanθ = sinθ / cosθ
= (cos26° cos64°)/sin64°
= [sin( 90° - 26° )] sin( 90° - 64° ) / sin64° --->cosθ = sin(90° - θ)
= sin64°sin26° / sin64°
= sin26°
= cos26° / (sin64° / cos64°) --->tanθ = sinθ / cosθ
= (cos26° cos64°)/sin64°
= [sin( 90° - 26° )] sin( 90° - 64° ) / sin64° --->cosθ = sin(90° - θ)
= sin64°sin26° / sin64°
= sin26°
參考: me and my brain
收錄日期: 2021-04-22 00:39:13
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090617000051KK01918