Luam fiecare paranteza in parte:
n+1/2n+5 =>n+1/2n+5
n+1/n+1 =>n+1/2n+2
Le scadem: n+1/3=>(n+3,2n+5)=3
n+2/2n+7=>n+2/2n+7
n+2/n+2 =>n+2/2n+4
Le scadem:n+2/3=>(n+2,2n+7)=3
n+1002/2n+2007=>n+1002/2n+2007
n+1002/n+1002 => n+1002/2n+2004
Le scadem: n+1002/3=>(n+1002,2n+2007)=3
S=3+3+3
S=9