(1*1+2*2)/(1*2)+(2*2+3*3)/(2*3)+(3*3+4*4)/(3*4)+(4*4+5*5)/(4*5)+...+(2002*2002+2003*2003)

问题描述:

(1*1+2*2)/(1*2)+(2*2+3*3)/(2*3)+(3*3+4*4)/(3*4)+(4*4+5*5)/(4*5)+...+(2002*2002+2003*2003)
/(2002*2003)+(2003*2003+2004*2004)/2003*2004

[ n^2 +(n+1)^2] / [n*(n+1)] = (n+1)/n + n/(n+1)
= 2 + 1/n - 1/(n+1)
原式= 2*2003 + 1-1/2 +1/2-1/3 + .+ 1/2003-1/2004
= 4006 + 2003/2004