2分之1一般表示为1/2,而不是2/1 1/2+1/4+1/8+1/16+1/32+1/64+1/128 =1/2+1/4+1/8+1/16+1/32+1/64+(1/128+1/128)-1/128 =1/2+1/4+1/8+1/16+1/32+(1/64+1/64)-1/128 =1/2+1/4+1/8+1/16+(1/32+1/32)-1/128 =1/2+1/4+1/8...