(1)1/n(n+1)=1/n - 1/(n+1)
(2)由(1)可得,1/2 +1/2x3+ .+1/n(n+1)=1 - 1/2 +1/2 - 1/3 +.+1/n - 1/(n+1)
=1 - 1/(n+1)
所以(2)=2010/2011