1/2+3/4+7/8+……+255/256
=(1-1/2)+(1-1/4)+(1-1/8)+……+(1-1/256)
=(1+1+1+……+1)-(1/2+1/4+1/8+……+1/256)
=1×8-(1-1/256)
=8-255/256
=7又1/256
明白请采纳,
有新问题请求助,