1+2+....2004=
2004x(2004+1):2=
2004x2005:2=
4018020:2=2009010
2005+2x2009010=
2005+4018020=4020025
2005+2•(1+2+3+......+2004)=2005+2•2005•2004:2=2005+2005•2004=
2005•(1+2004)=2005•2005=2005 la puterea 2 este patrat perfect
Ma intreb,trebuia sa arati ca este patrat perfect?