令A=1/2^10+1/2^9+……+1/4+1/22A=1/2^9+1/2^8+……+1/2+1所以A=2A-A=1-1/2^10令B=1+2+2^2+……+2^9+2^102B=2+2^2+……+2^10+2^11B=2B-B=2^11-1所以原式=A+B=2^11-1/2^10