Răspunsuri

2014-10-06T23:29:40+03:00
Suma lui gauss
4x1-1+4x2-1+4x3-1+4x4-1+.......+4x500-1+2002
4(1+2+3+4+....+4x500)-500+2002=
4x501x500/2-500+2002=
2004x250-500+2002
2014-10-06T23:38:23+03:00
3+7+11+15+....2002=(1+2)+(3+4)+(5+6)+(7+8)+.....+(1000+1001)+2002
formula pt suma n(n+1):2
⇒2002(2002+1):2=1001*2003=2005003