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EdyMihai
a fost răspuns

Calculati suma

a) 2+4+6+ ... + 2006

Răspuns :

ValeriusSoft
Calcule:
2+4+6+...+2006 = 2(1+2+3+...+1003) 
1+2+3+...+1003 (folosim suma lui Gauss : n(n+1)/2)
=1003(1003+1)/2

2 × (1003×1004)/2 = 1003 × 1004 = 1.007.012
2+4+6+...+2006=2*1+2*2+2*3+...+2*1003=2(1+2+3+..+1003)=2(1003*1004/2)=1003*1004=1007012 sper