(1-1/2^2)(1-1/3^2)(1-1/4^2)……(1-1/1004^2),
=(1-1/1004^2)(1+1/004^2)
=答案自己算
望采纳!!!
(1-1/2)(1+1/2)(1-1/3)(1+1/3)......(1-1/1004)(1+1/1004)=
(1/2*2/3*3/4*......1002/1003*1003/1004)(3/2*4/3*5/4*......1004/1003*1005/1004)
=1/1004*1005/2
=1005/2008
用平方差公式,然后分组求积:(1-1/2)(1+1/2)(1-1/3)(1+1/3)......(1-1/1004)(1+1/1004)=
(1/2*2/3*3/4*......1002/1003*1003/1004)(3/2*4/3*5/4*......1004/1003*1005/1004)
=1/1004*1005/2
=1005/2008
提示:把每个因式用平方差公式分解因式