如何將cos(θ-90)變成sinθ,help me plz
回答 (2)
2012-04-15 11:40 pm
✔ 最佳答案
cos(θ-90)=cos(360+θ-90)
=cos(270+θ)
=cos(180+90+θ)
=-cos(90+θ)
=sinθ
2012-04-15 15:43:29 補充：
or other method:
=cos(360+θ-90)
=cos(270+θ)
=cos{360-(90-θ)}
=cos(90-θ)
=sinθ
參考: ME, me
2012-04-16 4:47 am
收錄日期: 2021-04-13 18:38:28
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20120415000051KK00430