1×2/x+2×3/x+3×4/x+4×5/x+……+2007×2008/x
=x(1-1/2)+x(1/2-1/3)+x(1/3-1/4)+.+x(1/2007-1/2008)
=x(1-1/2+1/2-1/3+1/3-1/4+.+1/2007-1/2008)
=x(1-1/2008)
=2007x/2008
=2007
所以x=2008拜托，你把式子都抄错了，答案能对吗？最后是2007+2008/x，isn't 2007×2008/x1×2/x+2×3/x+3×4/x+4+5/x+……+2007+2008/x=2/x+6/x+12/x+5/x+6/x+.....+2008/x+(4+5+....+2007)=20/x+(5+6+....+2008)/x+(2007+4)(2007-4+1)/2=20/x+[(2008+5)(2008-5+1)/2]/x+2015022=20/x+2017026/x+2015022=2017046/x+2015022=2007x=-2017046/2013015