Question

I1/3-1/2I+I1/4-1/3I+I1/5-1/4I+……+I1/2009-1/2008I ？？？？

火速。先回答加分。先30。列式+道理再+30
2小时内回答

Answer 1

1/2-1/2009

I1/3-1/2I+I1/4-1/3I+I1/5-1/4I+……+I1/2009-1/2008I
=1/2-1/3+1/3-1/4+1/4-1/5+...+1/2008-1/2009
=1/2-1/2009

Answer 2

I1/3-1/2I+I1/4-1/3I+I1/5-1/4I+……+I1/2009-1/2008
=[(1/2)-(1/3)]+[(1/3)-(1/4)]+…+[(1/2008)-(1/2009)]
=(1/2)-(1/2009)
=2007/4018