qq如何设置代理服务器:1/1+1/1+2+1/1+2+3+1/1+2+3+4+…………1/1+2+3+4+5+………………n
来源:百度文库 编辑:查人人中国名人网 时间:2024/05/04 21:16:14
要化简
1/1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+…………1/(1+2+3+4+5+………………n)
1/1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+…………1/(1+2+3+4+5+………………n)
由于原式最后一项1/1+2+3+4+5+………………n=1/[n*(n+1)/2]=2/[n*(n+1)]
又观察可发现,2/[n*(n+1)]=2*[1/n-1/(n+1)]
所以原式=2*(1-1/2)+2*(1/2-1/3)……+2*[1/n-1/(n+1)]
=2*[1-1/2+1/2-1/3+1/3-1/4+……+1/n-1/(n+1)]
发现可抵消很多项(如:-1/2+1/2=0)
可得原式=2*[1-1/(n+1)]=2*n/(n+1)
1/1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+…1/(1+2+3+4+5+…n)
=2{1/(1×2)+1/(2×3)+…+1/[n(n+1)]}
=2[1-1/2+1/2-1/3+…+1/n-1/(n+1)]
=2[1-1/(n+1)]
=2n/(n+1)
?
(1/2005-1)(1/2004-1)........(1/3-1)(1/2-1)
1+1/1+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+......+10
1/1+1/2+1/3+1/4+。。。。+1/N 是多少
(1-1/2)*(1+1/2)*(1-1/3)*(1+1/3)*……*(1-1/99)*(1+1/99)。
(1+1/2)*(1-1/2)(1+1/3)*(1-1/3)*.......(1+1/99))*(1-1/99)怎么做
lim[(1-1/4)(1-1/9)...(1-1/(n+1)^2]=?
s=1/1+1/1!+1/2!+1/3!+1/4!+....+1/25!
(1-1/2^2)(1-1/3^2)....(1-1/10^2)