97家齊女中
97家齊 No.9
已知正三角形ABC之邊長\(2\sqrt{3}\),如圖附件所示,若點H為正三角形ABC垂心,在\(\bar{BC}\)邊之延長線上取一點R,則直線\(\bar{HR}\)分別與\(\bar{AB}\)及\(\bar{AC}\)交P、Q兩點,則\(\frac{1}{\bar{HP}}*\frac{1}{\bar{HQ}}*\frac{1}{\bar{HR}}=?\)
97家齊 N0.10
在以原點\(O(0,0,0)\)為球心,半徑為1的單位圓上取一點\(A(a_{1},a_{2},a_{3})\),點A所對的另一點\(B(a_{3},a_{1},a_{2})\)有在這單位圓上,則\(\angle AOB\)之最大值為?
以上答題的觀念為何呢?
附件
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001.JPG
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2009-6-20 10:46