两个大于等于0的数之和为0,则这两个数分别为0,所以
a=2,b=1
1/2+1/(2*3)+1/(3*4)+1/(4*5)+、、、、+1/(2011+2012)
=1/2+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)、、、+(1/2011-1/2012)
=1/2+1/2-1/2012
=2011/2012
两个大于等于0的数之和为0,则这两个数分别为0,所以
a=2,b=1
1/2+1/(2*3)+1/(3*4)+1/(4*5)+、、、、+1/(2011+2012)
=1/2+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)、、、+(1/2011-1/2012)
=1/2+1/2-1/2012
=2011/2012