美国的数学竞赛难不难看看这道题就知道了
今天的题目是排列组合问题,来自美国的一次数学竞赛,解题所用知识不超过小学5年级. 题目(5星难度):有一个九边形的各边长...
2009 USAMO Problems真题及答案 完整版真题免费下载 +答案解析请参考文末 真题下载请前往【纯真题】小程序 Day 1 Problem 1 Given circles??and??intersecting at points??and?, let??be a line through the cent...
2010 USAMO Problems真题及答案 完整版真题免费下载 +答案解析请参考文末 Day 1 Problem 1 Let??be a convex pentagon inscribed in a semicircle of diameter?. Denote by?,?,?,??the feet of the perpendicular...
2011 USAMO Problems真题及答案 完整版真题免费下载 +答案解析请参考文末 Day 1 Problem 1 Let?,?,??be positive real numbers such that?. Prove that Problem 2 An integer is assigned to each vertex ...
2010 USAJMO Problems真题及答案 完整版真题免费下载 +答案解析请参考文末 Day 1 Problem 1 A permutation of the set of positive integers??is a sequence??such that each element of??appears precisely one ...
2011 USAJMO Problems真题及答案 完整版真题免费下载 +答案解析请参考文末 Day 1 Problem 1 Find, with proof, all positive integers??for which??is a perfect square. Problem 2 Let?,?,??be positive real nu...
2012 USAMO Problems真题及答案 完整版真题免费下载 +答案解析请参考文末 Day 1 Problem 1 Find all integers??such that among any??positive real numbers?,?,?,??withthere exist three that are the side len...
2013 USAMO Problems真题及答案 完整版真题免费下载 +答案解析请参考文末 Day 1 Problem 1 In triangle?, points??lie on sides??respectively. Let?,?,??denote the circumcircles of triangles?,?,?, respectiv...
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