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题目设A=48×(1/(3~2-4)+1/(4~2-4)+…+1/(100~2-4)),則与A最接近的正整数是()(A)18.(B)20。(C)24.(D)25.(05年初数竞)分析此题括号内的加数多达近百个,如果直接计算显然不可取,需寻找一种简便易行的“巧算”方法.通过观察我们可以发现:每个加数均是1/(n~2-4)的形式,而对于正整数n≥3,
The subject is set to A=48×(1/(3~2-4)+1/(4~2-4)+...+1/(100~2-4)), then the closest positive integer to A is ( (A) 18.(B)20. (C)24.(D)25. (Scaling at the beginning of the year of 05) Analysis of up to nearly a hundred addends in the brackets. If the direct calculation is obviously not desirable, it is necessary to find a simple and easy way By observing we can find that each addend is in the form of 1/(n~2-4), and for positive integers n≥3,