原式=(1+1/2)-(3-1/6)+(3+1/12)-(5-1/20)+(5+1/30)-(7-1/42)+(7+1/56)-(9-1/72)+(9+1/90) =1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90 =1+1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8...这是之前发的，才发出去就想到了怎么解决，不过还是谢谢。