Please go to http://aerodrive.twghwfns.edu.hk/~4s123/Q15.JPG and find the figure.
The question:In triangle ABC.D is the mid-point of BC.By considering b and using the Cosine Law,prove that AB^2+AC^2=2AD^2+2CD^2.
Thx~~~~
收錄日期: 2021-04-25 16:49:06
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061229000051KK03998