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1【AMM·题12245】Proposed by Jiahao Chen, Tsinghua University, Beijing, China. Suppose that two circles α and β, with centers P and Q, respectively, intersect orthogonally at A and B. Let CD be a diameter of β that is exterior to α. Let E and F be points on α such that CE and DF are tangent to α, with C and E on one side of PQ and D and F on the other side of PQ. Let S be the intersection of CF and QA, and let T be the intersection of DE and QB. Prove that ST is parallel to CD and is tangent to α.
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21100102想知道史先生的文章在哪里可以看到 哪里可以学习复对合这种方法?001011714123114143我目前是一个高一学生,想了解奥妙几何,但不知从哪个基础看起0110000100181333一个三角形的三个边的中线分别是3,4,5,求这个三角形的面积 _________________________________________________________ 【原帖地址】http://tieba.baidu.com/f?kz=34784472884