Răspuns:
Explicație pas cu pas:
2+4+6+8+...+2016+2018+2020 =
2 x (1 + 2 + 3 + 4 + ....... + 1010) =
2 x 1010 x (1010 +1) / 2 =
1010^2 + 1010
sau :
S = 2 + 4 + 6 + ..... + 2n = n^2 + n
2n = 2020
n = 2020/2
n = 1010
2+4+6+8+...+2016+2018+2020 = 1010^2 + 1010
x^2 + 1010 = 2 + 4 + 6 + 8 + ...+ 2016 + 2018 + 2020
x^2 + 1010 = 1010^2 + 1010
x^2 = 1010^2
x = 1010
#copaceibrainly