如果2/1+6/1+12/1·······n+(n+1)/1等于2006/2005那么n等于?
问题描述：
如果2/1+6/1+12/1·······n+(n+1)/1等于2006/2005那么n等于?
答
原式=1-1/2+1/2-1/3+1/3-1/4+.+1/n-1/(n+1)
=1-1/n
=(n-1)/n
=2005/2006
n=2006