Question

1/3 + 1/15 + 1/35 + 1/63 + 1/99 + 1/143 + 1/195 + 1/255 (A)A

Answer 1

1/3=(1/1-1/3)/2 1/15=(1/3-1/5)/2 1/35=(1/5-1/7)/2 1/63=(1/7-1/9)/2 1/99=(1/9-1/11)/2 1/143=(1/11-1/13)/2 1/195=(1/13-1/15)/2 1/255=(1/15-1/17)/2 上述相加=1/2-1/34=16/34=8/17