a☆b＝（b-a）/(a*b)则1☆2－2☆3－……2006☆2007-2007☆2008

a*b=(b-a)/ab
=1/a-1/b
1*2-2*3-3*4-.......-2006*2007-2007*2008
=1-1/2-1/2+1/3-1/3+1/4-......-1/2006+1/2007-1/2007+1/2008
=1-1+1/2008(消掉共同项）
=1/2008
a☆b＝（b-a）/(a*b)=1/a-1/b
所以原式=(1/1-1/2)-(1/2-1/3)-(1/3-1/4)-……-(1/2006-1/2007)-(1/2007-1/2008)=1/2008

a☆b＝（b-a）/(a*b)=1/a-1/b
1☆2－2☆3－……2006☆2007-2007☆2008
=1/1-1/2+1/2-1/3+1/3-1/4+……+1/2007-1/2008（中间全部消掉）
=1-1/2008
=2007/2008

a☆b＝（b-a）/(a*b)=1/a-1/b
所以原式=(1/1-1/2)-(1/2-1/3)-(1/3-1/4)-……-(1/2006-1/2007)-(1/2007-1/2008)=1/2008

a*b=(b-a)/ab
=1/a-1/b
1*2-2*3-3*4-.......-2006*2007-2007*2008
=1-1/2-1/2+1/3-1/3+1/4-......-1/2006+1/2007-1/2007+1/2008
=1-1+1/2008(消掉共同项）
=1/2008