1/x(x+2)+1/(x+1)(x+3)+1/(x+2)(x+4)+...+1/(x+2007)(x+2009)
问题描述:
1/x(x+2)+1/(x+1)(x+3)+1/(x+2)(x+4)+...+1/(x+2007)(x+2009)
过程 追
答
1/x(x+2)=(1/x-1/(x+2))/2
1/(x+1)(x+3)=(1/(x+1)-1/(x+3))/2
以此类推
答案是:(1/x+1/(x+1)-1/(x+2007)-1/(x+2009))/2...其他项都消掉了