1减1x2/+2x3/1+3x4/1……+2011x2012/1等于多少?

问题描述:

1减1x2/+2x3/1+3x4/1……+2011x2012/1等于多少?

10

1减1x2/+2x3/1+3x4/1……+2011x2012/1
=1-1/2+1/2-1/3+1/3-1/4+...+1/2011-1/2012
=1-1/2012
=2011/2012
即2012分之2011