Using a lemma: Suppose D is on the segment BC of triangle ABC, then AD (The proof of the lemma is trivial: using larger edge facing larger angle.) Proof of the problem: Suppose DE is in triangle ABC。Extend DE to intersect the triangle ABC with D'E'. WLOG, assume that D' is on AB, E' is on AC. Then DE AE'<=AC, BE'<=max(AB, BC). So max(AE', BE')<=max(AB, BC, CA). |
寒潭清在我做斑主后5、6天来到本坛,迟我10来天于8-20左右上任 斑竹。她是上天给我们坛的赏赐。我把Jenny+野菜花+寒潭清三MM 称为本坛的“尽善尽美”。她们的才华真使我汗颜。 她还有一题“正三角形的威力 4”(于8-18),我觉得更妙。有兴趣你 可看看(现在第11页上)。 欢迎你这位wxc的大版主光顾我们坛。 |
你怎么知道都是MM?也许有JJ呢。 至少你称野教授为MM是不够尊重。(不知其他两位是不是教授) |
MM,兄弟称为GG,为什么?---脑筋一转题 |
Sorry about the 野教授. It does not sound very good. But any one who is teaching at college level is a professor, only some are full professors. And I'm sure your students call you professor, not associate professor. I have never seen anyone calls anyone GG. (好肉麻) |
If you use 华闻查询 to search 标题 by GG in 幽你一默, 音乐欣赏...forums, you can see many JM called XD by GG, it is not 肉麻 at all. |
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