(1/2+1/3+------+1/2009)x(1+1/2+------+1/2008)-(1+1/2+------+1/2009)x(1/2+1/3+------+1/2008)
问题描述:
(1/2+1/3+------+1/2009)x(1+1/2+------+1/2008)-(1+1/2+------+1/2009)x(1/2+1/3+------+1/2008)
答
(1/2+1/3+------+1/2009)x(1+1/2+------+1/2008)-(1+1/2+------+1/2009)x(1/2+1/3+------+1/2008)=(1/2+1/3+------+1/2009+1-1)x(1+1/2+------+1/2008)-(1+1/2+------+1/2009)x(1/2+1/3+------+1/2008+1-1)=(1+1/2+1...