2013×(1/1×2+1/2×3+1/3×4+……1/+2011×2012+2012×2013)怎么算?
问题描述:
2013×(1/1×2+1/2×3+1/3×4+……1/+2011×2012+2012×2013)怎么算?
答
原式=2013×(1-1/2+1/2-1/3+……+1/2011-1/2012+1/2012-1/2013)
=2013×(1-1/2013)
=2012