Prove that (1-Sec 8A) / (1-Sec 4A) = Tan 8A / Tan 2A.?
回答 (2)
2019-02-24 2:17 am
cosx = cos(2x−x) = cos2xcosx+sin2xsinx
Divide by cosxcos2x for sec2x = 1+tan2xtanx or 1−sec2x = −tan2xtanx
Apply this for x=4A, 2A and divide results
Divide by cosxcos2x for sec2x = 1+tan2xtanx or 1−sec2x = −tan2xtanx
Apply this for x=4A, 2A and divide results
收錄日期: 2021-04-24 07:32:34
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20190223165816AAulyXo