原式=(2+4+6+8+10+……+20)+(1/2+1/4+1/8+1/16+1/32+……+1/1024)
=[(2+20)+(4+18)+(6+16)+(8+14)+(10+12)]+[(1+1/2)+(1/2-1/4)+(1/4-1/8)+.((1/512-1/11024)]
=110+(1-1/1024)
=110又1023/1024
原式=(2+4+6+8+10+……+20)+(1/2+1/4+1/8+1/16+1/32+……+1/1024)
=[(2+20)+(4+18)+(6+16)+(8+14)+(10+12)]+[(1+1/2)+(1/2-1/4)+(1/4-1/8)+.((1/512-1/11024)]
=110+(1-1/1024)
=110又1023/1024