(1-1/2 ^2)(1-1/3 ^2)(1-4/1 ^2)…(1-1/2006 ^2)(1-1/2007 ^2) 帮忙算一下,等於几
来源:百度知道 编辑:UC知道 时间:2024/09/22 10:31:54
(1-1/2 ^2)(1-1/3 ^2)(1-4/1 ^2)…(1-1/2006 ^2)(1-1/2007 ^2) 帮忙算一下,等於几
用平方差
= (1-1/2)(1+1/2)(1-1/3)(1+1/3)……(1-1/2007)(1+1/2007)
=(1/2)(3/2)(2/3)(4/3)……(2006/2007)(2008/2007)
中间约分
=(1/2)(2008/2007)
=1004/2007
1004/2007
各分式同分得:
(2^2-1)*(3^2-1)*……*(2007^2-1)/(2^2*……*2007^2)
=1*2……2006*3*……2008/(2^2*……*2007^2)
=2*2007*2008/2^2*2007^2
=1004/2007
1/2-1/2=?
(1+1/2)(1+1/2^2)(1+1/2^4)(1+1/2^8)
(1-1/2^2)*(1-1/3^2)*(1-1/4^2).......(1-1/100^2)
1+1/(1+2)+1/(1+2+3)+...+1/(1+2+3+...+100)
1+1/(1+2)+1/(1+2+3)+-------+1/(1+2+3+----+100)
1+1/1+2+1/1+2+3+...+1/1+2+3...+2000
1+1/1+2+1/1+2+3.........+1/1+2+3.....100
1*(1/1+2)*(1/1+2+3)*~~~*(1/1+2+~~~2005)=?
3/2=2+1/1*2=1/1+1/2
1/1^2+1/2^2+...+1/n^2<2