1-1/2-1/4-1/8-1/16-1/32-1/64=1-(1/2+1/4+1/8+1/16+1/32+1/64) 设S=1/2+1/4+1/8+1/16+1/32+1/64 S/2=1/4+1/8+1/16+1/32+1/64+1/128 S-S/2=1/2-1/128 S/2=63/128 S=63/64 1-1/2-1/4-1/8-1/16-1/32-1/64 =1-63/64 =1/64
64分之1
1/64