有數唔識時(a.maths)
回答 (2)
2008-02-20 3:17 am
✔ 最佳答案
cos(-290)=cos(290)
= cos(360 - 290)
= cos 70
2008-02-19 7:42 am
cos(-290)
= cos(360 - 290)
= cos 70
= cos(360 - 290)
= cos 70
收錄日期: 2021-04-16 22:55:29
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080218000051KK04193