Question

Va rog, DAU COROANA!

Answer 1

1.se da 2 factor comun si se obtine suma lui Gauss pt n=100
2 (1+2+3+...+100)=2×100 (100+1)÷2=100×101=10100
2. Se da factor comun 6, respectiv 2
6 (1+2+...+100)÷[2 (1+2+...+100)]=6÷2=3
3.pt a putea calcula nr A , completam suma cu termenii care lipsesc pt a deveni suma lui Gauss, dar pt a nu modifica rezultatul sumei, ce adaugam scadem la final
A=1+2+3+4+5+...+2003+2004-(2+4+6+..+2004)
A=2004×2005÷2-2 (1+2+3+..+1002)
A=2005×2004÷2-2×1003×1002÷2
A=2005×1002-1002×1003
A=1002 (2005-1003)
A=1002×1002
A=1002^2 pp