1/3+1/6+1/12+1/24+……+1/3*2^n-1+……=
问题描述:
1/3+1/6+1/12+1/24+……+1/3*2^n-1+……=
同上
答
s=1/3+1/6+1/12+1/24+……+1/3*2^n-1s=2s-s=(2/3+1/3+1/6+...+1/3*2^n-2)-(1/3+1/6+1/12+1/24+……+1/3*2^n-1)=2/3-1/3*2^n-1=(2^(n) -1)/3*2^(n-1)