If a,b,c are angles of triangle
proof that 'tan(a/2)tan(b/2)+tan(b/2)tan(c/2)+tan(c/2)tan(a/2)=1'
math question
2010-02-10 3:08 am
回答 (1)
2010-02-10 3:33 am
✔ 最佳答案
====================================================圖片參考：http://img23.imageshack.us/img23/1959/31398610.png
2010-02-09 19:33:42 補充：
http://img23.imageshack.us/img23/1959/31398610.png
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100209000051KK01070