1/3+1/15+1/35.+1/2013×2015 简便计算
问题描述:
1/3+1/15+1/35.+1/2013×2015 简便计算
答
=1/1×3+1/3×5+……+1/2013×2015
=1/2×(1-1/3+1/3-1/5+……+1/2013-1/2015)
=1/2×(1-1/2015)
=1007/2015