Răspunsuri

2014-05-12T22:06:26+03:00
F(1)=1+1=2
f(2)=2+1=3
f(3)=3+1=4
...............
f(55)=55+1=56

S=(2+56)*55/2= 58*55/2= 29*55=1595 -nu este numar par
2014-05-12T22:19:48+03:00
Avem de calculat suma 2+3+4+....+56=(1+2+2+4+...+56)-1=56·57/2-1=28·57-1=numar par -1=numar impar