原式=1/2(1/2-1/梁吵昌4)+1/2(1/4-1/6)+...+1/碰纯2(1/2006-1/2008)
=1/2(1/2-1/4+1/4-1/6+...+1/2006-1/2008)
=1/2(1/2-1/2008)
=1/2(1003/2008)橡扒
=1003/4016
1/没亩樱2*4=1/2(1/2-1/4)
1/4*6=1/枯丛2(1/4-1/6)
原式=1/2(1/2-1/4)+1/2(1/4-1/6)+...+1/耐橡2(1/2006-1/2008)
=1/2(1/2-1/4+1/4-1/6+...+1/2006-1/2008)
=1/2(1/2-1/2008)
=1/2(1003/2008)
=1003/4016
给昌侍你个李迅绝思路---
参哪姿考1+2+3...+100
1+100 + 2+99 + 3+98 ......100/2=50
101*50=5050
1003/4016