1994+1/2-(1+1/3)+(2+1/2)-(3+1/3)+(4+1/2)-(5+1/3)+......+(1992+1/2)-(1999+1/3)

来源:百度知道 编辑:UC知道 时间:2024/06/08 10:37:35

1994+1/2-(1+1/3)+(2+1/2)-(3+1/3)+(4+1/2)-(5+1/3)+......+(1992+1/2)-(1999+1/3)
=1994+1/2-4/3+5/2-10/3+9/2-16/3+......+3985/2-5980/3

由1/2-4/3=-5/6
5/2-10/3=-5/6
...
3985/2-5980/3=-5/6(减数与被减数都加2,其差不变)
1994+1/2-4/3+5/2-10/3+9/2-16/3+......+3985/2-5980/3=1994+(1/2-4/3)+(5/2-10/3)+(9/2-16/3)+......+(3985/2-5980/3)=1994-5/6*[(3985-1)/4+1]=1994-5/6*997=-1163.167

1127又1/3

最后一项1999应该是1993吧??
答案是1994/2*(1+1/6)=1163+1/6