Răspuns :
Răspuns:
1+2+3+...+2021 = (2021×2022)/2 suma Gauss
a = 2 × (2021×2022)/2 - 2021
a = 2021×2022 - 2021
a = 2021(2022 - 1)
a = 2021×2021 = 2021^2 pătrat perfect
Răspuns:
1+2+3+...+2021 = (2021×2022)/2 suma Gauss
a = 2 × (2021×2022)/2 - 2021
a = 2021×2022 - 2021
a = 2021(2022 - 1)
a = 2021×2021 = 2021^2 pătrat perfect