1/1乘2乘3+1/2乘3乘4+...+1/98乘99乘100=

学习 时间:2026-05-29 02:55:19 阅读:1091
1/1乘2乘3+1/2乘3乘4+...+1/98乘99乘100=

最佳回答

等待的长颈鹿

调皮的小海豚

2026-05-29 02:55:19

1/(1*2*3)+1/(2*3*4)+。。。+1/(98*99*100)=(1/2)[1/(1*2)-1/(2*3)]+(1/2)[1/(2*3)-1/(3*4)]+。。。+(1/2)[1/(98*99)-1/(99*100)]=(1/2)[1/(1*2)]-(1/2)[1/(2*3)]+(1/2)[1/(2*3)]-(1/2)[1/(3*4)]+。。。+(1/2)[1/(98*99)]-(1/2)[1/(99*100)]中间的全部互相抵消,所以=(1/2)[1/(1*2)]-(1/2)[1/(99*100)]=4949/19800

最新回答共有2条回答

  • 直率的荷花
    回复
    2026-05-29 02:55:19

    1/(1*2*3)+1/(2*3*4)+。。。+1/(98*99*100)=(1/2)[1/(1*2)-1/(2*3)]+(1/2)[1/(2*3)-1/(3*4)]+。。。+(1/2)[1/(98*99)-1/(99*100)]=(1/2)[1/(1*2)]-(1/2)[1/(2*3)]+(1/2)[1/(2*3)]-(1/2)[1/(3*4)]+。。。+(1/2)[1/(98*99)]-(1/2)[1/(99*100)]中间的全部互相抵消,所以=(1/2)[1/(1*2)]-(1/2)[1/(99*100)]=4949/19800

上一篇 三年级暑假作业语文中的3篇小动物观察日记是不是写同一种动物?

下一篇 化学平衡的标志都有哪些?