1
超级简单
3/2*4/3*5/4*...21/20=21/2
1-1/2+1/2-1/3+1/3-1/4+1/4-1/5.+1/99-1/100=1-1/100=99/100
老弟,我的过程还不够详细吗?
1-1/2=1/1*2
1/2-1/3=1/(2*3)
1/n-1/(n+1)=1/[n(n+1)]
1
超级简单
3/2*4/3*5/4*...21/20=21/2
1-1/2+1/2-1/3+1/3-1/4+1/4-1/5.+1/99-1/100=1-1/100=99/100
老弟,我的过程还不够详细吗?
1-1/2=1/1*2
1/2-1/3=1/(2*3)
1/n-1/(n+1)=1/[n(n+1)]