1/2!+2/3!+3/4!......+(n-1)/n!
来源:百度知道 编辑:UC知道 时间:2024/06/07 18:34:15
化简上式
原式应该是这样的吧1/(2!)+2/(3!)+3/(4!)+……+n-1/(n!)=?
原式=[1/(2-1)!-1/(2!)]+{1/(3-1)!-1/3!]+……+[1/(n-1)!-1/n!]
=1/1!-1/2!+1/2!-1/3!+......+1/(n-1)!-1/n!
=1-1/n!
=n!-1/n!
有公式的~~~
注意:(n-1)/n!=(n/n!)-(1/n!)=(1/(n-1)!)-(1/n!)
所以,原式
=(1/1!-1/2!)+(1/2!-1/3!)+......+(1/(n-1)!-1/n!)
=1-1/n!
=(n!-1)/n!
1/2-1/2=?
3/2=2+1/1*2=1/1+1/2
1/(x-2)+2/(x+1)-2/(x-1)-1/(x+2)
2/3,1/2,2/5,1/3,2/7 ()?
(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)
1/2,3/2,1/5,-1/8,-2/13,(?)
1/1^2+1/2^2+...+1/n^2<2
1+2/1+2/2+2/1+3/1+3/2+3/3+3/2+3/1+......+100/1+100/2+......100/100+100/99+.....+100/1
1+1/(1+2)+1/(1+2+3)+...+1/(1+2+3+...+100)