有數唔識(a.maths)
回答 (1)
2008-01-28 12:20 am
✔ 最佳答案
csc(-580°) =-csc580°
=-csc(360°+220°)
=-csc(220°)
=-csc(180°+40°)
=csc(40°)
[P.S.正負號的運算可參照CAST圖]
收錄日期: 2021-04-25 17:19:39
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080127000051KK02006