S=根号(1+1/1^2+1/2^2)+根号(1+1/2^2+1/3^2)+.+根号(1+1/2003^2+1/2004

[1+1/n-1/(n+1)]^2
=[1+1/n(n+1)]^2
=1+2/n(n+1)+[1/n(n+1)]^2
=1+2/n(n+1)+[1/n-1/(n+1)]^2(平方展开)
=1+1/n^2+1/(n+1)^2
所以S＝(1+1/1-1/2)+(1+1/2-1/3)+……+(1+1/2003-1/2004)
=2003-1/2004
所以S的整数部分是2002