sin(-x+270)=??
cos(x-180)=??
sin cos tan
2006-11-21 2:50 am
回答 (2)
2006-11-21 2:58 am
✔ 最佳答案
sin(-x+270)=??=sin(270-x)
= -cosx
cos(x-180)=??
= cos(180-x)
= -cosx
2006-11-20 19:01:32 補充：
270-x 是第三象限，sin 為負值將 270-x 變函數時 sin→coscos(-x)=cosx180-x是二象限，cos為負值將180-x 變函數是cos不變，仍為cos
2006-11-21 2:59 am
sin (-x+270)
=sin (270-x)
=-cos x
cos (x-180)
=cos (-180+x)
=cos (180+x)
=-cos x
=sin (270-x)
=-cos x
cos (x-180)
=cos (-180+x)
=cos (180+x)
=-cos x
收錄日期: 2021-04-23 00:08:07
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061120000051KK03169