1-1/2-1/4-1/8-1/16-1/32-.-1/1024
=1-(1/2+1/4+1/8+.+1/1024)
=1-(512+256+128+64+32+16+8+4+2+1)/1024
=1-1023/1024
=1/10241-(512+256+128+64+32+16+8+4+2+1)/1024这一步是什么意思1/2+1/4+1/8+.......+1/1024=512/1024+256/1204+128/1024+.....+1/1024(这一步是通分）=(512+256+128+64+32+16+8+4+2+1)/1024=1023/1024