1/1*2+1/2*3+1/3*4+……1/99*100+1/100*101=?坐等,

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1/1*2+1/2*3+1/3*4+……1/99*100+1/100*101=?坐等,
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1/1*2+1/2*3+1/3*4+……1/99*100+1/100*101=?坐等,
1/1*2+1/2*3+1/3*4+……1/99*100+1/100*101=?坐等,

1/1*2+1/2*3+1/3*4+……1/99*100+1/100*101=?坐等,
1/1×2=1/2=1-1/2
1/2×3=1/6=1/2-1/3
1/3×4=1/12=1/3-1/4
.
1/100×101=1/10001=1/100-1/101
1/1×2+1/2×3+1/3×4+…+1/100×101
=1-1/2+1/2-1/3+1/3-1/4+...++1/99-1/100+1/100-1/101
=1+(-1/2+1/2)+(-1/3+1/3)-1/4+...++1/98+(-1/99+1/99)+(-1/100+1/100)-1/101
=1-1/101
=100/101

100/101

100/101

通过上述公式分解式子:

1/1-1/2+1/2-1/3+1/3-1/4+..............+1/99-1/100+1/100-1/101,除了第一项和最后项,其他每2项可以消去,最后化简为  1/1-1/101=1-1/101

1/1*2+1/2*3+1/3*4+……1/99*100+1/100*101
=1/1-1/2+1/2-1/3+...+1/99-1/100+1/100-1/101
=1-1/101
=100/101

原式=1-1/2+1/2-1/3+1/3-1/4+......+1/99-1/100+1/100-1/101=1-1/101=100/101