1/2+1/4+1/8+1/16+1/2的n次方

问题描述:

1/2+1/4+1/8+1/16+1/2的n次方

1/2+1/4=1-1/4=3/4
1/2+1/4+1/8=1-1/8=7/8
……
1/2+1/4+1/8+1/16+……+1/2的n次方=1-1/2的n次方=(2的n次方-1)/2的n次方