3/1+1/15+1/35+1/63+1/99+1/143 简便计算

3/1+1/15+1/35+1/63+1/99+1/143 简便计算
3/1+1/15+1/35+1/63+1/99+1/143 简便计算

3/1+1/15+1/35+1/63+1/99+1/143 简便计算
1/3+1/15+1/35+1/63+1/99+1/143
=1/2 (2/3+2/15+2/35+2/63+2/99+2/143)
=1/2 (1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13)
=1/2(1-1/13)
=6/13