(1x2分之1)+(2x3分之1)+(3x4分之1)······(99x100分之1)等于多少?

问题描述:

(1x2分之1)+(2x3分之1)+(3x4分之1)······(99x100分之1)等于多少?

1/1×2 +1/2×3 +1/3×4+1/4×5+......1/98×99+1/99×100
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+......+1/98-1/99+1/99-1/100
=1-1/100
=99/100

*:乘号
1/(1*2) +1/(2*3) +1/(3*4)+...+1/(99*100)
=(1/1 -1/2) +(1/2 -1/3)+(1/3 -1/4) +...+(1/99 -1/100)
=1 -1/100
=99/100