Răspuns :
Răspuns:
M=2021+2•(1+2+3+...+2020)
paranteza o calculam cu suma lui Gauss
M=2021+2·(2020·2021)/2
M=2021+4082420
M=4084441=2021×2021=2021²→ pp
√4084441=2021
M = 2021+ 2((2020•2021)/2) - (suma Gauss)
M = 2021 + 2(1010•2021
M= 2021 + 2020 • 2021
M = 2021(1 + 2020) - (factor comun 2021)
M = 2021•2021 = 2021^2 ——> patrat perfect
M = 2021 + 2(1010•2021
M= 2021 + 2020 • 2021
M = 2021(1 + 2020) - (factor comun 2021)
M = 2021•2021 = 2021^2 ——> patrat perfect