1/2x5+1/5x8+1/8x11+.+1/2006x2009+2009x2013用裂项法计算
问题描述：
1/2x5+1/5x8+1/8x11+.+1/2006x2009+2009x2013用裂项法计算
答
=1/3*(1/2-1/5)+1/3*(1/5-1/8)+.+1/3*(1/2006-1/2009)+1/3*(1/2009-1/2013)
=1/3*(1/2-1/5+1/5-1/8+.+1/2006-1/2009+1/2009-1/2013)
=1/3*(1/2-1/2013)
=1/3*1/2011
=1/6033