2/11*13+2/13*15+2/15*17+2/17*19+2/19*21+2/21*23+1/23
问题描述:
2/11*13+2/13*15+2/15*17+2/17*19+2/19*21+2/21*23+1/23
答
2/11*13+2/13*15+2/15*17+2/17*19+2/19*21+2/21*23+1/23
=1/11-1/13+1/13-1/15+1/15-1/17+1/17-1/19+1/19-1/21+1/21-1/23+1/23
=1/11