1/2+1/4+1/8+.....+1/2^2007=?
来源:百度知道 编辑:UC知道 时间:2024/06/24 14:13:08
这是首项是1/2,公比是1/2的等比数列前2007项的和
1/2+1/4+1/8+.....+1/2^2007
=(1/2)*[1-(1/2)^2007]/(1-1/2)
=1-(1/2^2007)
设S=1/2+1/4+1/8+.....+1/2^2007
则2S=1+1/2+1/4+1/8+.....+1/2^2006+1/2^2007-1/2^2007=1+S-1/2^2007
所以S=1-1/2^2007
1/2+1/4+1/8+.....+1/2^2007
=1/2+1/4+1/8+.....+1/2^2007-1+1
=-1/2+1/4+1/8+.....+1/2^2007+1
=-1/4+1/8+.....+1/2^2007+1
=-1/8+1/16+.....+1/2^2007+1
....
=-1/2^2007+1
设S=原式,则2S=1+1/2+1/4+....+1/2^2006,
∴原式=2S-原式=1-1/2^2007=(2^2007-1)/2^2007
(1+1/2+1/3+1/4)×
1/1+1/2+1/3+1/4+。。。。+1/N 是多少
1/1+1/2+1/3+1/4+......1/2002=?
1-1/2+1/3-1/4+........1/99-1/100
1+1/2+1+1/3+1+1/4+......+1/100=?
(1/2) (1/4+1/6)=
(1-1/2)(1-1/3)(1-1/4)(1-1/5).....(1-1/1000)
(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)
s=1/1+1/1!+1/2!+1/3!+1/4!+....+1/25!