1、题干是不是应该是S=1/(1/2001+1/2002+.......1/2010)=?
因为:1/(10/2010)>1/(1/2001+1/2002+1/2003+1/2004+……+1/2010)>1/(10/2001)
即:201>1/(1/2001+1/2002+1/2003+1/2004+……+1/2010)>200.1
所以:1/(1/2001+1/2002+1/2003+1/2004+……+1/2010)≈200
所以整数部分是200
1、问题补充里面是说,1/42=1/()-1/()吗?
1/42=1/6-1/7
2、(1)原式是不是写反了?应该是1/(1*2)+1/(2*3)+1/(3*4)+...+1/(99*100)
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+...+(1/99-1/100)
=1-1/2+1/2-1/3+1/3-1/4+...+1/99-1/100
=1-1/100
=99/100
(2)这个式子也是分子分母写倒了?