Question

1/2+1/6+1/12+1/20+……+1/2005*2006 详细过程

Answer 1

1/2+1/2*3+1/3*4+1/4*5........+1/2005*2006
=1/2+1/2-1/3+1/3-1/4+1/4-1/5........+1/2005-1/2006
=1/2+1/2-1/2006
=1-1/2006
=2005/2006

Answer 2

首先你要认识到1/n*(n+1)=1/n－1/(n+1)，其中n为正整数，然后过程同楼上。