1/x(x+1) + 1/(x+1)(x+2) + 1/(x+2)(x+3) +.+1/(x+2010)(x+2011)
=1/x-1/(x+1) + 1/(x+1)-1/(x+2) + 1/(x+2)-1/(x+3) +.+1/(x+2010)-1/(x+2011)
=1/x-1/(x+2011)
=2011/x(x+2011)