一條簡單prove題(2)
回答 (1)
2009-01-11 3:19 am
✔ 最佳答案
not so easy !tan(π/4 +φ)
=(tan(π/4)+ tanφ)/1-tan(π/4)tanφ
=(1+ tanφ)/(1- tanφ)
=(1+ tanφ)(1+ tanφ)/(1- tanφ)(1+ tanφ)
=(1+ tan^2φ+ 2tanφ)/(1- tan^2φ)
=(1+ tan^2φ)/(1- tan^2φ) + (2tanφ)/(1- tan^2φ)
= sec2φ+ tan2φ
[(1+ tan^2φ)/(1- tan^2φ) 用萬能公式轉]
收錄日期: 2021-04-25 16:59:09
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090110000051KK01464