设 S=1+2/3+3/3^2+4/3^3+……+101/3^100则S/3=1/3+2/3^2+3/3^3+...+101/3^101上式减下式可得2S/3=1+1/3+1/3^2+1/3^3+...+1/3^100-101/3^101而1+1/3+1/3^2+1/3^3+...+1/3^100=(1-1/3^101)/[1-1/3]=(3/2)(1-1/3^101)这...