1/2 +3/4+ 4/8 +5/16....+11/2的十次方=(2-3/2)+(2-5/4)+(5/4-6/8)+(6/8-7/16)+……+(12/2^9-13/2^10)=2-3/2+2-13/2^10=5/2-13/2^10=1267/512.