1/(1×2)+1/(2×3)+1/(3×4)+1(4×5)+......+1/(99×100)等于多少?
来源:百度知道 编辑:UC知道 时间:2024/06/05 18:12:05
我是初一的学生.请用初中方法解答.谢谢!
1/(1×2)+1/(2×3)+1/(3×4)+1(4×5)+......+1/(99×100)
=1/2+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+.....+(1/99-1/100)
=1/2+1/2-1/100
=1-1/100
=99/100
就是这样...看德懂吧.?!
1/(1*2)=1/1-1/2
1/(2*3)=1/2-1/3
以此类推
1/1-1/2+1/2-1/3……-1/99+1/99-1/100=99/100
原式=1-(1/2)+(1/2)-(1/3)+(1/3)-(1/4)+(1/4)……-(1/99)+(1/99)-(1/100)(接着抵消)
=1-(1/100)
=99/100
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+----+100)
1 3 2 1 x
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+2+3)+(1+2+3+4)+...(1+2+3+...+100)=
1,1,1,2,3,5,9,()
依次计算1,1+2+1,1+2+3+2+1,1+2+3+4+3+2+1,...
(-1)+(-1)2+(-1)3+...+(-1)2n
1/3+1/5+1/7+~~~~~~1/2n+1