(-1*1/2)+(-2*1/3)+(-3/1*1

(-1*1/2)+(-2*1/3)+(-3/1*1/4)+...+(-1/2009*2010)+(-1/2010*1/2

1个回答

(-1*1/2)+(-2*1/3)+(-3/1*1/4)+...+(-1/2009*2010)+(-1/2010*1/2011)
= -1×（1-1/2+1/2-1/3+……+1/2010-1/2011）
= -1×2010/2011
= -2010/2011