1/x(x+2)+1/x(x+2)(x+4)+1/(x+4)(x+6)+……1(x+2004)(x+2006)

问题描述:

1/x(x+2)+1/x(x+2)(x+4)+1/(x+4)(x+6)+……1(x+2004)(x+2006)

第二个多了个X吧?
原式=[1/x-1/(x+2)]/2+[1/(x+2)-1/(x+4)]/2+...+[1/(x+2004)-1/(x+2006)]/2
=[1/x-1/(x+2006)]/2
=2005/2x(x+2006)