tailieunhanh - ĐỀ THI TOÁN APMO (CHÂU Á THÁI BÌNH DƯƠNG)_ĐỀ 34

Tham khảo tài liệu 'đề thi toán apmo (châu á thái bình dương)_đề 34', khoa học tự nhiên, toán học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 10th Asian Pacific Mathematics Olympiad March 1998 Time allowed 4 hours. No calculators to be used. Each question is worth 7points. 1. LetFbe the set of all n-tuples A1 A2 . An where each A. i 1 2 . n is a subset of 1 2 . 1998 . Let I A I denote the number of elements of the set A. Find the number yI A uA2 u-uAn . A1 A2 .A 2. Show that for any positive integers a and b 36a b a 36b cannot be a power of 2. 3. Let a b c be positive real numbers. Prove that a N b N c A 1 a 1 - 1 - 2 1 I b 1 c 1 a J I a b c A 3 V abc J 4. Let ABC be a triangle and D the foot of the altitude from A. Let E and F be on a line through D such that AE is perpendicular to BE AF is perpendicular to CF and E and F are different from D. Let M and N be the midpoints of the line segments BC and EF respectively. Prove that AN is perpendicular to NM. 5. Determine the largest of all integers n with the property that n is divisible by all positive integers that are less than 3jn . END OF .

TỪ KHÓA LIÊN QUAN