1/2+1/2*3+1/3*4+1/4*5+...+1/9*10
来源:百度知道 编辑:UC知道 时间:2024/06/15 20:39:42
1/2+1/2*3+1/3*4+1/4*5+...+1/9*10
=1/2+1/2-1/3+1/3-1/4+...+1/9-1/10
=1/2+1/2-1/10
=9/10
原式=1/2+1/2-1/3+1/3-1/4+1/4-1/5…………+1/9-1/10
=1/2+1/2-1/10
=9/10
主要是裂项相消法,哈哈,希望能帮到你!!
9+1/2+(1/2+1/3+...1/9)
=
题目没写对,应该是1/2+1/(2*3)+1/(3*4)+1/(4*5)+...+1/(9*10)
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+~~~2005)=?
1+1/2+1/3+.....+1/n
1+1/2+1/3+...+1/100
1-1/2+1/3-.....-1/10
(1+1/2+1/3+1/4)×
3/2=2+1/1*2=1/1+1/2
(1/2005-1)(1/2004-1)........(1/3-1)(1/2-1)