(1-1/2^2)(1-1/3^2)……(1-1/2004^2)=?

来源:百度知道 编辑:UC知道 时间:2024/04/28 23:14:47
(1-1/2^2)(1-1/3^2)……(1-1/2004^2)=

1-1/n^2=(n^2-1)/n^2=(n-1)(n+1)/n^2

(1-1/2^2)(1-1/3^2)……(1-1/2004^2)
=1*3/2^2*2*4/3^2*3*5/4^2*...*2003*2005/2004^2
=(1*2005)/(2*2004)
=2005/4008.

0
1-1=0
0/任何数=0
0乘任何数=0
所以最后还是0

2005/4008
不懂上HI百度

=(1+1/2)(1-1/2)(1+1/3)(1-1/3)...(1+1/2004)(1-1/2004)
=(1+1/2)(1+1/3)...(1+1/2004)((1-1/2)(1-1/3)...(1-1/2004)
=3/2*4/3*5/4*...*2005/2004*1/2*2/3*3/4*...*2003/2004
=2005/2 *1/2004
=2005/4008

原式=(1-1/2)(1+1/2)(1-1/3)(1+1/3)........(1-1/2004)(1+1/2004)
=(1-1/2)(1-1/3)......(1-1/2004)(1+1/2)(1+1/3).....(1+1/2004)
=(1/2)(2/3)(3/4)...(2003/2004)(3/2)(4/3)...(2004/2003)(2005/2004)
=(1/2)(2005/2004)
=2005/4008