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AOï¼BOï¼COï¼åå«å¨æ¹æ¯ä»Dï¼Eï¼Fï¼å¨BD / DC * CE /è¿ä¸ªæ é¢EA * AF / FB = 1
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åæ¶ååâ³ABDç´COFï¼â´BC / CD * DO / OA * AF / DF =1â¡
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æ®å¡ç¦å®çéå®çï¼å 为ï¼ADï¼DBï¼*ï¼BEï¼ECï¼*ï¼CFï¼FAï¼= [ï¼CD * CTGAï¼/ [ï¼CD * ctgBï¼] * [ï¼AE * ctgBï¼/ï¼AE * CTGCï¼] * [ï¼BF * CTGCï¼/åå·¥å¼æï¼AE * ctgBï¼] = 1ï¼æ以ä¸ä¸ªé«çCDï¼AEï¼BFç¸äº¤äºä¸ç¹ã
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