在∆ABC中,証明
(a)sin²A=sin²B+sin²C-2sinBsinCcosA
(b)(sin²A+sin²C)/sin²B=(a²+c²)/b²
(c)a²+b²+c²=2(bccosA+cacosB+abcosC)
a-maths~~~~~~~~~
2007-10-12 3:01 pm
回答 (1)
2007-10-12 5:48 pm
參考: My Maths knowledge
收錄日期: 2021-04-23 20:38:42
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https://hk.answers.yahoo.com/question/index?qid=20071012000051KK00478