作业帮 > 数学 > 作业

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

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/27 11:55:26
1994+1/2-(1+1/3)+(2+1/2)-(3+1/3)+(4+1/2)-(5+1/3)+.+(1992+1/2)-(1993+1/3) 光写算式我看不懂.
1994+1/2-(1+1/3)+(2+1/2)-(3+1/3)+(4+1/2)-(5+1/3)+.+(1992+1/2)-(1993+1/3)
=-(1+1/3)+(2+1/2)-(3+1/3)+(4+1/2)-(5+1/3)+.+(1992+1/2)-(1993+1/3)+(1994+1/2)
=-1-1/3+2+1/2-3-1/3+4+1/2-5-1/3+.+1992+1/2-1993-1/3+1994+1/2
=(-1+2-3+4-5+…+1992-1993+1994)+(-1/3+1/2-1/3+1/2-1/3+…+1/2-1/3+1/2)
=【(-1+2)+(-3+4)+…+(-1993+1994)】+(-1/3-1/3-…-1/3)+(1/2+1/2+…+1/2)
=1994/2+(-1/3)*(1994/2)+(1/2*1994/2)
=997-997/3+997/2
=1163又1/6.