Question

(2+4+6+...+2012)-(1+3+...+2011)= va rog frumos ajutor!

Answer 1

(2+4+6+...+2012)-(1+3+...+2011)
Prima suma
S1=(2+4+6+...+2012)= 2* (1+2+3+....+1006)= 2*1006*1007 : 2=1 013 042


A doua suma
 S2=(1+3+...+2011)

1+3+5+...+2n-1 =n*n;
2n-1=2011
2n=2010 / :2
n=1005
S= 1005 * 1005=1 010 025


S1 -S 2=1 013 042 - 1 010 025= 3017