m的3次方-2m的平方+m/m的3次方-m,其中m=2011
(m的3次方-2m的平方+m)/(m的3次方-m)
=m(m-1)²/[m(m+1)(m-1)]
=(m-1)/(m+1)
=(2011-1)/(2011+1)
=1005/1006