1*2分子1+2*3分之1+3*4分之1+n(n+1)分之1
=1-1/2+1/2-1/3+1/3-1/4……+1/n-1/(n+1)
=1-1/(n+1)
=(n+1-1)/(n+1)
=n/(n+1)
望采纳
1*2分之1+2*3分之1+3*4分之1+n(n+1)分之1
=1-1/2+1/2-1/3+1/3-1/4+1/4……+1/n-1/(n+1)
=1-1/(n+1)
=(n+1-1)/(n+1)
=n/(n+1)
内容全部来源于网络收集，如有侵权，请联系网站删除：QQ：24596024