play我呸歌曲百度云:一道数学题

来源:百度文库 编辑:高校问答 时间:2024/04/28 11:38:46
(1-1/2^2)(1-1/3^2)(1-1/4^2)……(1-1/2005^2)(1-1/2006^2)的值

正确答案
2007/4012

原式=(1-1/2)(1+1/2)(1-1/3)(1-1/3)(1-1/4)(1+1/4)....(1-1/2006)(+1/2006)
=1/2×2/3×3/4....2005/2006×3/2×4/3×5/4×6/5....×2007/2006

消去整理得到 =1/2006×2007/2
=2007/4012

原式 = 1/2(1-1/2)(1-1/3)(1-1/4)……(1-1/2005)(1-1/2006)
= 1/2(1/2)(2/3)(3/4)……(2004/2005)(2005/2006)
= 1/2(1/2006)
= 1/4012

原式=(1-1/2)(1+1/2)(1-1/3)......(1-1/2006)(1+1/2006)
=1/4012